Tüm alıştırma soruları

5556 soru

Soru 2041Soru

In the standard (x,y)(x,y) coordinate plane, a line has the equation 3x+2y=123x + 2y = 12. What is the xx-intercept of this line?

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Cevap: 4

Cevap

The xx-intercept of the line is 44.

Adım Adım Çözüm

1
Substitute y=0y = 0 into the equation to find the point where the line intersects the xx-axis.
3x+2(0)=123x + 2(0) = 12
By definition, the xx-intercept occurs where the yy-coordinate is equal to 00.
2
Simplify the equation and solve for the variable xx.
3x=12x=43x = 12 \Rightarrow x = 4
Simplifying 2(0)2(0) to 00 leaves 3x=123x = 12. Dividing both sides of the equation by 33 isolates xx, giving x=4x = 4.

Anahtar Kavram

Determining the xx-intercept of a linear equation by evaluating it at y=0y = 0.
Tahmini Süre:45s
Soru 2042Soru
Consider the system of equations below:
y=x+37y = \sqrt{x + 37}
y=x5y = x - 5
If (x,y)(x, y) is a real solution to this system, what is the value of xyxy?
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Cevap: 84

Cevap

84
The correct answer is 84 because solving the system yields the quadratic equation x211x12=0x^2 - 11x - 12 = 0, which has roots x=12x = 12 and x=1x = -1. Substituting these back into the original equations shows that only x=12x = 12 is valid (giving y=7y = 7), while x=1x = -1 is extraneous (since 36=66\sqrt{36} = 6 \neq -6). The product of the coordinates of the valid solution is 12×7=8412 \times 7 = 84.

Adım Adım Çözüm

1
Set the two expressions for yy equal to each other to solve for xx.
x+37=x5\sqrt{x + 37} = x - 5
Since both equations are solved for yy, their right-hand sides must be equal at the point of intersection.
2
Square both sides of the equation to eliminate the radical.
x+37=(x5)2x+37=x210x+25x + 37 = (x - 5)^2 \Rightarrow x + 37 = x^2 - 10x + 25
Squaring is the inverse operation of the square root. The binomial on the right must be expanded fully using (ab)2=a22ab+b2(a-b)^2 = a^2 - 2ab + b^2.
3
Rearrange the quadratic equation into standard form.
x211x12=0x^2 - 11x - 12 = 0
Subtracting xx and 3737 from both sides sets the quadratic equation to zero so it can be solved.
4
Factor the quadratic equation to find the algebraic solutions.
(x12)(x+1)=0x=12 or x=1(x - 12)(x + 1) = 0 \Rightarrow x = 12 \text{ or } x = -1
Factoring the trinomial allows us to find the roots by setting each linear factor to zero.
5
Substitute each solution back into the original system to check for extraneous solutions.
For x=12x = 12: y=125=7y = 12 - 5 = 7 and y=12+37=7y = \sqrt{12 + 37} = 7 (Valid). For x=1x = -1: y=15=6y = -1 - 5 = -6, but y=1+37=66y = \sqrt{-1 + 37} = 6 \neq -6 (Extraneous).
Squaring both sides of an equation can introduce extraneous solutions that do not satisfy the original radical relationship because the principal square root must be non-negative.
6
Calculate the product xyxy of the coordinates of the valid solution.
xy=12×7=84xy = 12 \times 7 = 84
The question asks for the product of xx and yy for the real solution (12,7)(12, 7).

Anahtar Kavram

Solving systems containing radical equations and verifying for extraneous solutions.
Soru 2043Soru

If 23(3x4)14(x+2)=223\frac{2}{3}(3x - 4) - \frac{1}{4}(x + 2) = \frac{22}{3}, what is the value of 3x+23x + 2?

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Cevap: 20

Cevap

The correct answer is 20, which is the value of the expression 3x+23x + 2 when x=6x = 6.
The value of the expression 3x+23x + 2 is 20. Solving the linear equation 23(3x4)14(x+2)=223\frac{2}{3}(3x - 4) - \frac{1}{4}(x + 2) = \frac{22}{3} yields x=6x = 6. Substituting x=6x = 6 into 3x+23x + 2 gives 3(6)+2=203(6) + 2 = 20.

Adım Adım Çözüm

1
Multiply the entire equation by the least common multiple of the denominators (12).
8(3x4)3(x+2)=888(3x - 4) - 3(x + 2) = 88
This clears the fractions to make solving the equation simpler.
2
Distribute the coefficients to remove parentheses.
24x323x6=8824x - 32 - 3x - 6 = 88
This allows like terms to be grouped together.
3
Combine like terms on the left side of the equation.
21x38=8821x - 38 = 88
Simplifies the equation to prepare for isolating the variable.
4
Add 38 to both sides of the equation.
21x=12621x = 126
Isolates the variable term on one side of the equation.
5
Divide both sides by 21 to solve for xx.
x=6x = 6
Finds the value of the variable xx.
6
Substitute x=6x = 6 into the target expression 3x+23x + 2.
3(6)+2=203(6) + 2 = 20
Calculates the final requested value.

Anahtar Kavram

Solving multi-step linear equations with fractions and evaluating algebraic expressions.
Soru 2044Soru

For a certain real number xx, the equation 34(x3)13(2x+5)=2\frac{3}{4}(x - 3) - \frac{1}{3}(2x + 5) = -2 is true. What is the value of 2x52x - 5?

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Cevap: 41

Cevap

The value of the expression 2x52x - 5 is 41.
Solving the linear equation by multiplying both sides by the least common denominator of 12 yields the simplified equation 9(x3)4(2x+5)=249(x - 3) - 4(2x + 5) = -24. Expanding the terms gives 9x278x20=249x - 27 - 8x - 20 = -24, which simplifies to x47=24x - 47 = -24. Adding 47 to both sides gives x=23x = 23. Finally, evaluating the expression 2x52x - 5 for x=23x = 23 results in 2(23)5=412(23) - 5 = 41.

Adım Adım Çözüm

1
Multiply both sides of the equation by the least common denominator of 12 to eliminate fractions.
9(x3)4(2x+5)=249(x - 3) - 4(2x + 5) = -24
Multiplying by the LCD clears all fractional coefficients, making the equation easier to solve.
2
Distribute the constants and expand the terms on the left side of the equation.
9x278x20=249x - 27 - 8x - 20 = -24
Applying the distributive property removes the parentheses.
3
Combine like terms on the left side of the equation.
x47=24x - 47 = -24
Simplifying the equation makes it easier to isolate the variable xx.
4
Isolate the variable xx by adding 47 to both sides of the equation.
x=23x = 23
This determines the value of the unknown variable xx.
5
Substitute x=23x = 23 into the target expression 2x52x - 5.
4141
The question asks for the value of the expression 2x52x - 5, not just the value of xx.

Anahtar Kavram

Solving multi-step linear equations with fractional coefficients by clearing the denominators and then evaluating algebraic expressions.

Alternatif Yöntem

Instead of multiplying by the LCD first, distribute the fractions directly: 34x9423x53=2\frac{3}{4}x - \frac{9}{4} - \frac{2}{3}x - \frac{5}{3} = -2. Combine the xx terms: (3423)x=112x(\frac{3}{4} - \frac{2}{3})x = \frac{1}{12}x. Combine the constant terms: 9453=27122012=4712-\frac{9}{4} - \frac{5}{3} = -\frac{27}{12} - \frac{20}{12} = -\frac{47}{12}. This gives the equation 112x4712=2\frac{1}{12}x - \frac{47}{12} = -2. Add 4712\frac{47}{12} to both sides: 112x=2+4712=2412+4712=2312\frac{1}{12}x = -2 + \frac{47}{12} = -\frac{24}{12} + \frac{47}{12} = \frac{23}{12}. Multiply by 12 to get x=23x = 23, then evaluate 2x5=412x - 5 = 41.
Tahmini Süre:1m 30s
Soru 2045Soru

Matrices AA and BB are defined as:

A=[x432],B=[1253]A = \begin{bmatrix} x & 4 \\ -3 & 2 \end{bmatrix}, \quad B = \begin{bmatrix} 1 & -2 \\ 5 & 3 \end{bmatrix}

Let CC represent the product matrix ABAB, where:

C=[c11c12c21c22]C = \begin{bmatrix} c_{11} & c_{12} \\ c_{21} & c_{22} \end{bmatrix}

If the element c12c_{12} is equal to 22, what is the value of xx?

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Cevap: 5

Cevap

5
To find the entry c12c_{12} in the first row and second column of the product matrix C=ABC = AB, we calculate the dot product of the first row of matrix AA and the second column of matrix BB. The first row of AA is [x,4][x, 4] and the second column of BB is [2,3]T[-2, 3]^T. Thus, c12=x(2)+4(3)=2x+12c_{12} = x(-2) + 4(3) = -2x + 12. Setting this equal to the given value of 22 gives the equation 2x+12=2-2x + 12 = 2. Subtracting 1212 from both sides results in 2x=10-2x = -10. Dividing by 2-2 yields x=5x = 5.

Adım Adım Çözüm

1
Identify the formula for the element c12c_{12} in the product matrix C=ABC = AB.
c12=2x+12c_{12} = -2x + 12
The element c12c_{12} is located in the first row and second column of the product matrix, so it is the product of the first row of AA, which is [x,4][x, 4], and the second column of BB, which is [2,3]T[-2, 3]^T.
2
Set the expression for c12c_{12} equal to the given value of 22 and solve the linear equation for xx.
x=5x = 5
Setting 2x+12=2-2x + 12 = 2 leads to 2x=10-2x = -10, and dividing both sides by 2-2 yields x=5x = 5.

Anahtar Kavram

Matrix Multiplication and Element-wise Operations
Soru 2046Soru

If xx and yy are positive real numbers greater than 11 such that logy(x)+6logx(y)=5\log_y(x) + 6\log_x(y) = 5 and xy=64xy = 64, what is the sum of all possible values of xx?

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Cevap: 16+16216 + 16\sqrt{2}

Cevap

16+16216 + 16\sqrt{2}
Using the change of base property logx(y)=1logy(x)\log_x(y) = \frac{1}{\log_y(x)}, the equation can be written in terms of u=logy(x)u = \log_y(x) as u+6u=5u + \frac{6}{u} = 5. Solving this quadratic equation gives u=2u = 2 or u=3u = 3. If logy(x)=2\log_y(x) = 2, then x=y2x = y^2. Substituting into xy=64xy = 64 yields y3=64    y=4y^3 = 64 \implies y = 4, which gives x=16x = 16. If logy(x)=3\log_y(x) = 3, then x=y3x = y^3. Substituting into xy=64xy = 64 yields y4=64    y=22y^4 = 64 \implies y = 2\sqrt{2}, which gives x=162x = 16\sqrt{2}. The sum of these values is 16+16216 + 16\sqrt{2}.

Adım Adım Çözüm

1
Apply the change of base formula to express the equation in terms of a single logarithmic base.
Since logx(y)=1logy(x)\log_x(y) = \frac{1}{\log_y(x)}, the equation logy(x)+6logx(y)=5\log_y(x) + 6\log_x(y) = 5 becomes logy(x)+6logy(x)=5\log_y(x) + \frac{6}{\log_y(x)} = 5.
This allows us to solve for the log expression using substitution.
2
Substitute u=logy(x)u = \log_y(x) and solve the resulting quadratic equation for uu.
u+6u=5    u25u+6=0    (u2)(u3)=0u + \frac{6}{u} = 5 \implies u^2 - 5u + 6 = 0 \implies (u-2)(u-3) = 0, so u=2u = 2 or u=3u = 3.
Solving the quadratic equation gives the possible relationships between xx and yy.
3
Analyze the first case where u=2u = 2 and solve for xx.
If logy(x)=2\log_y(x) = 2, then x=y2x = y^2. Substituting this into xy=64xy = 64 gives y3=64y^3 = 64, which yields y=4y = 4. Thus, x=42=16x = 4^2 = 16.
This determines the first possible value of xx.
4
Analyze the second case where u=3u = 3 and solve for xx.
If logy(x)=3\log_y(x) = 3, then x=y3x = y^3. Substituting this into xy=64xy = 64 gives y4=64y^4 = 64, which yields y=641/4=(26)1/4=23/2=22y = 64^{1/4} = (2^6)^{1/4} = 2^{3/2} = 2\sqrt{2}. Thus, x=(22)3=162x = (2\sqrt{2})^3 = 16\sqrt{2}.
This determines the second possible value of xx.
5
Sum the possible values of xx.
16+16216 + 16\sqrt{2}
The question asks for the sum of all possible values of xx.

Anahtar Kavram

Solving systems of exponential and logarithmic equations using base-change properties and substitution

Alternatif Yöntem

Instead of using substitution directly, you can write both equations in terms of base 2 or natural logs: let logy(x)=k\log_y(x) = k, which means x=ykx = y^k. We then have k+6/k=5k + 6/k = 5 giving k=2k = 2 or k=3k = 3. This leads directly to x=y2x = y^2 and x=y3x = y^3, which can then be substituted into the second equation.
Tahmini Süre:3m 0s
Soru 2047Soru

A community theater group sells student tickets and adult tickets for their weekend plays. The number of tickets sold for Friday and Saturday night shows is represented by the matrix TT:

T=[80120100150]T = \begin{bmatrix} 80 & 120 \\ 100 & 150 \end{bmatrix}

where the first and second rows represent Friday and Saturday, respectively, and the first and second columns represent student and adult tickets, respectively. The price of each ticket is represented by the matrix PP:

P=[610]P = \begin{bmatrix} 6 \\ 10 \end{bmatrix}

where the first row represents the price of a student ticket (6)andthesecondrowrepresentsthepriceofanadultticket(6) and the second row represents the price of an adult ticket ( 10). Which of the following matrices represents the total ticket sales revenue, in dollars, for Friday and Saturday, respectively?

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Cevap: [1,6802,100]\begin{bmatrix} 1,680 \\ 2,100 \end{bmatrix}

Cevap

The matrix with entries 1,680 and 2,100
The correct answer is the matrix with entries 1,680 and 2,100. This is found by multiplying the sales matrix by the price matrix. The revenue for Friday is calculated as 80×6+120×10=480+1,200=1,68080 \times 6 + 120 \times 10 = 480 + 1,200 = 1,680. The revenue for Saturday is 100×6+150×10=600+1,500=2,100100 \times 6 + 150 \times 10 = 600 + 1,500 = 2,100. Placing these in a column matrix matching the order of the days yields the correct matrix.

Adım Adım Çözüm

1
Set up the matrix multiplication of the ticket sales matrix TT and the ticket price matrix PP.
TP=[80120100150][610]TP = \begin{bmatrix} 80 & 120 \\ 100 & 150 \end{bmatrix} \begin{bmatrix} 6 \\ 10 \end{bmatrix}
To find the total revenue for Friday and Saturday, we must multiply the ticket sales by their respective prices.
2
Perform the multiplication by taking the dot product of each row of TT with the column of PP.
[80(6)+120(10)100(6)+150(10)]=[480+1200600+1500]\begin{bmatrix} 80(6) + 120(10) \\ 100(6) + 150(10) \end{bmatrix} = \begin{bmatrix} 480 + 1200 \\ 600 + 1500 \end{bmatrix}
The matrix product of a 2×22 \times 2 matrix and a 2×12 \times 1 matrix results in a 2×12 \times 1 matrix where the entries are the sums of the products of corresponding elements.
3
Simplify the sums in the resulting matrix.
[1,6802,100]\begin{bmatrix} 1,680 \\ 2,100 \end{bmatrix}
Adding the products gives the final total revenues for Friday and Saturday, respectively.

Anahtar Kavram

Matrix Multiplication in Word Problems

Alternatif Yöntem

Instead of formal matrix multiplication, you can calculate the scalar totals for each day directly (Friday: 80×6+120×10=1,68080 \times 6 + 120 \times 10 = 1,680; Saturday: 100×6+150×10=2,100100 \times 6 + 150 \times 10 = 2,100) and match them with the corresponding rows of the resulting 2×12 \times 1 matrix.
Tahmini Süre:1m 30s
Soru 2048Soru

The slope of a line is 22, and the line passes through the point (3,1)(3, 1). What is the yy-intercept of this line in the standard (x,y)(x,y) coordinate plane?

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Cevap: 5-5

Cevap

The yy-intercept of the line is 5-5.
The correct answer is found by substituting the slope m=2m = 2 and the point (3,1)(3, 1) into the slope-intercept equation y=mx+by = mx + b. This gives 1=2(3)+b1 = 2(3) + b, which simplifies to 1=6+b1 = 6 + b. Subtracting 66 from both sides isolates bb, giving b=5b = -5.

Adım Adım Çözüm

1
Recall the slope-intercept form of a linear equation.
y=mx+by = mx + b, where mm is the slope and bb is the yy-intercept.
This formula allows us to solve for the yy-intercept using the given slope and a point on the line.
2
Substitute the given slope m=2m = 2 and the coordinates of the point (3,1)(3, 1) into the slope-intercept equation.
1=2(3)+b1 = 2(3) + b
The point (3,1)(3, 1) lies on the line, so its coordinates must satisfy the equation of the line.
3
Simplify the equation and solve for bb.
1=6+bb=51 = 6 + b \Rightarrow b = -5
Subtracting 66 from both sides isolates bb, which represents the yy-intercept of the line.

Anahtar Kavram

Linear Equations and Graphing
Soru 2049Soru

If xx is a positive real number such that log2(x)+log4(x)+log16(x)=7\log_2(x) + \log_4(x) + \log_{16}(x) = 7, what is the value of xx?

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Cevap: 16

Cevap

The value of xx is 1616.
By converting all logarithms to base 2, we write log4(x)\log_4(x) as 12log2(x)\frac{1}{2}\log_2(x) and log16(x)\log_{16}(x) as 14log2(x)\frac{1}{4}\log_2(x). Summing these gives 74log2(x)=7\frac{7}{4}\log_2(x) = 7, which simplifies to log2(x)=4\log_2(x) = 4. Converting to exponential form, we find x=24=16x = 2^4 = 16.

Adım Adım Çözüm

1
Apply the change of base formula to express the logarithms with a common base of 2.
log4(x)=12log2(x)\log_4(x) = \frac{1}{2}\log_2(x) and log16(x)=14log2(x)\log_{16}(x) = \frac{1}{4}\log_2(x), giving the equation log2(x)+12log2(x)+14log2(x)=7\log_2(x) + \frac{1}{2}\log_2(x) + \frac{1}{4}\log_2(x) = 7.
Rewriting the terms with a common base allows them to be combined algebraically.
2
Combine the coefficients of the like terms on the left-hand side.
74log2(x)=7\frac{7}{4}\log_2(x) = 7.
The sum of the coefficients is 1+12+14=44+24+14=741 + \frac{1}{2} + \frac{1}{4} = \frac{4}{4} + \frac{2}{4} + \frac{1}{4} = \frac{7}{4}.
3
Isolate the logarithm term by dividing or multiplying by the reciprocal coefficient.
log2(x)=4\log_2(x) = 4.
Multiplying both sides by 47\frac{4}{7} solves for the value of log2(x)\log_2(x).
4
Convert the equation from logarithmic form to its equivalent exponential form.
x=24=16x = 2^4 = 16.
By definition, logb(a)=c\log_b(a) = c is equivalent to bc=ab^c = a.

Anahtar Kavram

Change of Base Formula for Logarithms
Soru 2050Soru

Let the functions ff and gg be defined for all real numbers by f(x)=2x616f(x) = |2x - 6| - 16 and g(x)=(x3)25g(x) = (x - 3)^2 - 5. What is the sum of all real values of xx that satisfy the equation f(g(x))=0f(g(x)) = 0?

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Cevap: 9

Cevap

9
The correct answer is 9. First, substitute the inner function into the outer function to get f(g(x))=2g(x)616=0f(g(x)) = |2g(x) - 6| - 16 = 0. This simplifies to the absolute value equation 2g(x)6=16|2g(x) - 6| = 16. Splitting this into its two possible cases gives 2g(x)6=16    g(x)=112g(x) - 6 = 16 \implies g(x) = 11, and 2g(x)6=16    g(x)=52g(x) - 6 = -16 \implies g(x) = -5. Solving the first case, (x3)25=11    (x3)2=16(x-3)^2 - 5 = 11 \implies (x-3)^2 = 16. Taking both square roots yields x3=4    x=7x - 3 = 4 \implies x = 7 and x3=4    x=1x - 3 = -4 \implies x = -1. Solving the second case, (x3)25=5    (x3)2=0    x3=0    x=3(x-3)^2 - 5 = -5 \implies (x-3)^2 = 0 \implies x - 3 = 0 \implies x = 3. The sum of all unique real values of xx that satisfy the original equation is 7+(1)+3=97 + (-1) + 3 = 9.

Adım Adım Çözüm

1
Set up the composite function equation using the outer function definition.
2g(x)616=0|2g(x) - 6| - 16 = 0
Substitute the expression of g(x)g(x) as the input variable into f(x)f(x).
2
Isolate the absolute value term and split the equation into two cases.
2g(x)6=16    2g(x)6=16|2g(x) - 6| = 16 \implies 2g(x) - 6 = 16 or 2g(x)6=162g(x) - 6 = -16
An absolute value equation of the form A=B|A| = B where B>0B > 0 has two solutions: A=BA = B and A=BA = -B.
3
Solve for the target values of g(x)g(x) in each case.
g(x)=11g(x) = 11 and g(x)=5g(x) = -5
Isolate the function g(x)g(x) by adding 6 and dividing by 2 on both sides of each equation.
4
Solve the first case g(x)=11g(x) = 11 for the variable xx.
(x3)25=11    (x3)2=16    x3=±4(x-3)^2 - 5 = 11 \implies (x-3)^2 = 16 \implies x - 3 = \pm 4, yielding x=7x = 7 and x=1x = -1
Substitute the algebraic rule for g(x)g(x), isolate the squared expression, and extract the square roots.
5
Solve the second case g(x)=5g(x) = -5 for the variable xx.
(x3)25=5    (x3)2=0    x3=0(x-3)^2 - 5 = -5 \implies (x-3)^2 = 0 \implies x - 3 = 0, yielding x=3x = 3
Substitute the algebraic rule for g(x)g(x), isolate the squared expression, and solve for xx.
6
Sum all unique real solutions found.
7+(1)+3=97 + (-1) + 3 = 9
Add the distinct solutions x=7x = 7, x=1x = -1, and x=3x = 3 to find the total sum.

Anahtar Kavram

Evaluating and solving equations involving composite functions, absolute values, and quadratic expressions.
Soru 2051Soru

If log2(a)+log2(b)=5\log_2(a) + \log_2(b) = 5 and log2(a2)log2(b)=4\log_2(a^2) - \log_2(b) = 4 for positive real numbers aa and bb, what is the value of a+ba + b?

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Cevap: 12

Cevap

12
The correct answer is 12. We can simplify the system of equations by using the power rule of logarithms, which allows us to rewrite log2(a2)\log_2(a^2) as 2log2(a)2\log_2(a). Letting x=log2(a)x = \log_2(a) and y=log2(b)y = \log_2(b) gives us the system x+y=5x + y = 5 and 2xy=42x - y = 4. Adding these equations gives 3x=93x = 9, which means x=3x = 3. Substituting this back gives y=2y = 2. Converting back from logarithmic form to exponential form, we get a=23=8a = 2^3 = 8 and b=22=4b = 2^2 = 4. Therefore, a+b=8+4=12a + b = 8 + 4 = 12.

Adım Adım Çözüm

1
Use the power property of logarithms, logb(xk)=klogb(x)\log_b(x^k) = k \log_b(x), to rewrite the second equation.
The equation log2(a2)log2(b)=4\log_2(a^2) - \log_2(b) = 4 becomes 2log2(a)log2(b)=42\log_2(a) - \log_2(b) = 4.
This simplifies the term log2(a2)\log_2(a^2) so that it is linear in terms of log2(a)\log_2(a).
2
Substitute variables to simplify solving the system of equations. Let x=log2(a)x = \log_2(a) and y=log2(b)y = \log_2(b).
The system of equations becomes:
1) x+y=5x + y = 5
2) 2xy=42x - y = 4
Variable substitution reduces the logarithmic system to a standard system of linear equations.
3
Solve the linear system by adding the two equations together.
Adding the equations yields (x+y)+(2xy)=5+4(x + y) + (2x - y) = 5 + 4, which simplifies to 3x=93x = 9, so x=3x = 3. Substituting x=3x = 3 back into the first equation gives 3+y=53 + y = 5, so y=2y = 2.
Addition eliminates the variable yy, allowing us to solve for xx and then find yy.
4
Convert the solved values of xx and yy back into aa and bb using the exponential form definition of a logarithm.
Since x=log2(a)=3x = \log_2(a) = 3, we have a=23=8a = 2^3 = 8. Since y=log2(b)=2y = \log_2(b) = 2, we have b=22=4b = 2^2 = 4.
The definition of a logarithm logb(z)=w\log_b(z) = w is equivalent to z=bwz = b^w.
5
Calculate the sum of aa and bb.
a+b=8+4=12a + b = 8 + 4 = 12.
To find the final value requested by the question stem.

Anahtar Kavram

Solving systems of logarithmic equations using logarithm properties and exponential conversions
Soru 2052Soru

A system of equations consists of the circle defined by x2+(y4)2=10x^2 + (y - 4)^2 = 10 and the line defined by y=2x1y = 2x - 1. The two points of intersection of this system and the origin, (0,0)(0, 0), form the vertices of a triangle in the standard (x,y)(x, y) coordinate plane. What is the area of this triangle?

Cevabı ve açıklamayı göster

Cevap: 1

Cevap

The correct area of the triangle is 1.
The correct answer of 1 is found by substituting the linear equation into the circle's equation, solving the resulting quadratic equation to find the coordinates of the two intersection points, (1,1)(1, 1) and (3,5)(3, 5), and then applying the coordinate area formula for a triangle with a vertex at the origin.

Adım Adım Çözüm

1
Substitute the linear equation into the circle's equation to form a quadratic equation in terms of xx.
x2+(2x5)2=10x^2 + (2x - 5)^2 = 10
This allows us to solve for the x-coordinates of the intersection points by replacing yy with 2x12x - 1 in (y4)2(y - 4)^2 to get (2x5)2(2x - 5)^2.
2
Expand the squared binomial and simplify the quadratic equation.
5x220x+15=05x^2 - 20x + 15 = 0
Expanding (2x5)2(2x - 5)^2 yields 4x220x+254x^2 - 20x + 25. Adding x2x^2 and subtracting 1010 from both sides simplifies the equation to standard quadratic form.
3
Divide the quadratic equation by 5 and solve for xx by factoring.
x=1x = 1 and x=3x = 3
Dividing the equation by 5 yields x24x+3=0x^2 - 4x + 3 = 0, which factors as (x1)(x3)=0(x - 1)(x - 3) = 0.
4
Find the corresponding y-coordinates by substituting the xx-values back into the linear equation y=2x1y = 2x - 1.
The intersection points are (1,1)(1, 1) and (3,5)(3, 5).
For x=1x = 1, y=2(1)1=1y = 2(1) - 1 = 1. For x=3x = 3, y=2(3)1=5y = 2(3) - 1 = 5.
5
Calculate the area of the triangle with vertices at the origin (0,0)(0, 0) and the two intersection points (1,1)(1, 1) and (3,5)(3, 5).
Area = 1
Using the coordinate area formula for a triangle with one vertex at the origin, Area=12x1y2x2y1=121(5)3(1)=122=1\text{Area} = \frac{1}{2} |x_1 y_2 - x_2 y_1| = \frac{1}{2} |1(5) - 3(1)| = \frac{1}{2} |2| = 1.

Anahtar Kavram

Solving a system of linear and non-linear equations and using coordinate geometry to find the area of a triangle.

Alternatif Yöntem

Instead of using the coordinate area formula, we can find the distance between the two intersection points to serve as the base of the triangle (b=(31)2+(51)2=25b = \sqrt{(3-1)^2 + (5-1)^2} = 2\sqrt{5}), and find the perpendicular distance from the origin to the line 2xy1=02x - y - 1 = 0 to serve as the height (h=122+(1)2=15h = \frac{|-1|}{\sqrt{2^2 + (-1)^2}} = \frac{1}{\sqrt{5}}). The area is then 12×25×15=1\frac{1}{2} \times 2\sqrt{5} \times \frac{1}{\sqrt{5}} = 1.
Tahmini Süre:2m 30s
Soru 2053Soru

In the inequality 732z+187 - 3|2z + 1| \ge -8, which of the following inequality expressions represents the complete solution set for zz?

Cevabı ve açıklamayı göster

Cevap: 3z2-3 \le z \le 2

Cevap

3z2-3 \le z \le 2
Subtracting 7 from both sides of 732z+187 - 3|2z + 1| \ge -8 yields 32z+115-3|2z + 1| \ge -15. Dividing both sides by 3-3 and reversing the inequality sign results in 2z+15|2z + 1| \le 5. Writing this as the compound inequality 52z+15-5 \le 2z + 1 \le 5, then subtracting 1 and dividing by 2 yields the correct solution interval 3z2-3 \le z \le 2.

Adım Adım Çözüm

1
Subtract 7 from both sides to begin isolating the absolute value term.
32z+115-3|2z + 1| \ge -15
To solve an absolute value inequality, we must first isolate the absolute value term on one side.
2
Divide both sides by -3 and reverse the direction of the inequality sign.
2z+15|2z + 1| \le 5
Dividing an inequality by a negative number reverses the direction of the inequality sign.
3
Rewrite the absolute value inequality as a compound inequality.
52z+15-5 \le 2z + 1 \le 5
An inequality of the form ua|u| \le a (where a0a \ge 0) is equivalent to the compound inequality aua-a \le u \le a.
4
Subtract 1 from all three parts of the compound inequality.
62z4-6 \le 2z \le 4
This is the first step to isolate the variable zz in the middle.
5
Divide all three parts by 2.
3z2-3 \le z \le 2
This fully isolates zz, giving the final solution interval.

Anahtar Kavram

Solving multi-step absolute value inequalities, including isolating the absolute value expression, reversing the inequality sign when dividing by a negative number, and expressing the solution as a compound inequality.
Soru 2054Soru

The length of a rectangle is 33 inches greater than its width. If the area of the rectangle is 1010 square inches, what is the width of the rectangle, in inches?

Cevabı ve açıklamayı göster

Cevap: 22

Cevap

The width of the rectangle is 22 inches.
The correct answer is the option stating that the width is 22 inches. This is obtained by expressing the length as w+3w+3 and setting the area equation to w(w+3)=10w(w+3) = 10. Expanding and setting it to zero gives the quadratic equation w2+3w10=0w^2 + 3w - 10 = 0, which factors to (w+5)(w2)=0(w+5)(w-2) = 0. Since width must be positive, the only valid solution is 22.

Adım Adım Çözüm

1
Define variables for the dimensions of the rectangle based on the problem statement.
Let the width of the rectangle be ww inches. The length of the rectangle is w+3w + 3 inches.
The problem states that the length is 33 inches greater than the width.
2
Set up an equation representing the area of the rectangle.
The area is the product of width and length: w(w+3)=10w(w + 3) = 10.
The area of a rectangle is calculated as width times length, and the given area is 1010 square inches.
3
Rewrite the equation in standard quadratic form aw2+bw+c=0aw^2 + bw + c = 0.
Distribute ww to get w2+3w=10w^2 + 3w = 10, then subtract 1010 from both sides: w2+3w10=0w^2 + 3w - 10 = 0.
Standard quadratic form is required to solve the equation by factoring or using the quadratic formula.
4
Factor the quadratic equation.
(w+5)(w2)=0(w + 5)(w - 2) = 0.
Finding factors that multiply to 10-10 and add to 33 allows us to find the roots.
5
Solve for ww and apply real-world constraints.
w=5w = -5 or w=2w = 2. Since a physical width must be positive, discard 5-5, leaving w=2w = 2.
A dimension of a geometric shape cannot be negative.

Anahtar Kavram

Solving quadratic equations derived from geometric word problems by factoring or using the quadratic formula.
Soru 2055Soru

A line in the standard (x,y)(x,y) coordinate plane is defined by the equation kx+5y=20kx + 5y = 20, where kk is a constant. If the xx-intercept of this line is 66 units greater than its yy-intercept, what is the value of kk?

Cevabı ve açıklamayı göster

Cevap: 22

Cevap

22
To find the yy-intercept of the line kx+5y=20kx + 5y = 20, set x=0x = 0, which yields 5y=205y = 20, or y=4y = 4. The problem states that the xx-intercept is 66 units greater than the yy-intercept, so the xx-intercept is 4+6=104 + 6 = 10. Substituting the point (10,0)(10, 0) back into the original equation gives k(10)+5(0)=20k(10) + 5(0) = 20. Solving for kk gives 10k=2010k = 20, which simplifies to k=2k = 2.

Adım Adım Çözüm

1
Find the yy-intercept of the line.
The yy-coordinate of the yy-intercept is 44.
To find the yy-intercept, set x=0x = 0 in the equation kx+5y=20kx + 5y = 20, which gives 5y=205y = 20, so y=4y = 4.
2
Determine the xx-intercept of the line based on the given relationship.
The xx-coordinate of the xx-intercept is 1010.
The problem states that the xx-intercept is 66 units greater than the yy-intercept. Since the yy-intercept value is 44, the xx-intercept value is 4+6=104 + 6 = 10.
3
Substitute the xx-intercept coordinates into the equation to solve for kk.
k=2k = 2
The xx-intercept is the point (10,0)(10, 0). Substituting x=10x = 10 and y=0y = 0 into the equation kx+5y=20kx + 5y = 20 gives k(10)+5(0)=20k(10) + 5(0) = 20, which simplifies to 10k=2010k = 20. Dividing both sides by 1010 yields k=2k = 2.

Anahtar Kavram

Finding intercepts of a linear equation in standard form and using coordinate substitution to solve for an unknown coefficient.
Soru 2056Soru

Which of the following inequalities represents the complete set of real values of xx that satisfy the inequality 1534x15 \leq 3 - 4x?

Cevabı ve açıklamayı göster

Cevap: x3x \leq -3

Cevap

The inequality x3x \leq -3
Subtracting 3 from both sides of the inequality 1534x15 \leq 3 - 4x yields 124x12 \leq -4x. Dividing both sides by 4-4 and reversing the inequality sign results in 3x-3 \geq x, which is equivalent to x3x \leq -3.

Adım Adım Çözüm

1
Subtract 3 from both sides of the inequality.
124x12 \leq -4x
This isolates the variable term on the right side of the inequality.
2
Divide both sides of the inequality by 4-4 and reverse the inequality sign.
3x-3 \geq x
Reversing the inequality sign is required whenever both sides of an inequality are multiplied or divided by a negative number.
3
Rewrite the inequality to place the variable on the left side.
x3x \leq -3
Reorganizing the inequality with xx on the left side is the standard format for representing the solution set.

Anahtar Kavram

Solving linear inequalities by isolating the variable and reversing the inequality sign when dividing by a negative number.
Soru 2057Soru

A local library has two types of books: fiction and non-fiction. The number of fiction books is 120120 more than twice the number of non-fiction books. If the library has a total of 18601\text{}860 books, how many more fiction books than non-fiction books does the library have?

Cevabı ve açıklamayı göster

Cevap: 700700

Cevap

The library has 700700 more fiction books than non-fiction books.
The correct answer is 700700 because defining the non-fiction books as nn gives 2n+1202n + 120 fiction books. Summing these to equal 18601860 yields 3n+120=18603n + 120 = 1860, which solves to n=580n = 580. The number of fiction books is therefore 2(580)+120=12802(580) + 120 = 1280. The difference between the two quantities is 1280580=7001280 - 580 = 700.

Adım Adım Çözüm

1
Define variables for the two categories of books.
Let nn be the number of non-fiction books. Then the number of fiction books, ff, can be written as f=2n+120f = 2n + 120.
This translates the statement 'the number of fiction books is 120120 more than twice the number of non-fiction books' into an algebraic expression.
2
Set up an equation representing the total number of books.
n+f=1860    n+(2n+120)=1860    3n+120=1860n + f = 1860 \implies n + (2n + 120) = 1860 \implies 3n + 120 = 1860.
The sum of the fiction and non-fiction books must equal the total library inventory of 18601860 books.
3
Solve the equation for the number of non-fiction books, nn.
3n=1740    n=5803n = 1740 \implies n = 580.
Subtracting 120120 from both sides and then dividing by 33 isolates the variable nn.
4
Calculate the number of fiction books and find the difference.
Fiction books: f=2(580)+120=1280f = 2(580) + 120 = 1280. Difference: fn=1280580=700f - n = 1280 - 580 = 700.
The question asks for the difference between the number of fiction and non-fiction books.

Anahtar Kavram

Translating and Solving Algebraic Word Problems
Tahmini Süre:1m 30s
Soru 2058Soru

A certain relationship between a number xx and other values is described as follows: one-fourth of the difference when 3x3x is subtracted from 22, decreased by one-third of the sum of xx and 33, is strictly greater than the difference when xx is subtracted from 11. Which of the following inequalities represents the complete set of all possible values of xx?

Cevabı ve açıklamayı göster

Cevap: x<18x < -18

Cevap

x<18x < -18
To find the correct solution set, translate the word problem into the inequality 23x4x+33>1x\frac{2 - 3x}{4} - \frac{x + 3}{3} > 1 - x. First, multiply all terms by the least common denominator, 1212, to clear the fractions, giving 3(23x)4(x+3)>12(1x)3(2 - 3x) - 4(x + 3) > 12(1 - x). Distributing the constants yields 69x4x12>1212x6 - 9x - 4x - 12 > 12 - 12x. Combining like terms on the left side simplifies the expression to 13x6>1212x-13x - 6 > 12 - 12x. Adding 12x12x to both sides results in x6>12-x - 6 > 12. Adding 66 to both sides gives x>18-x > 18. Finally, dividing by 1-1 and reversing the inequality sign results in the solution set x<18x < -18.

Adım Adım Çözüm

1
Translate the verbal description into an algebraic inequality.
23x4x+33>1x\frac{2 - 3x}{4} - \frac{x + 3}{3} > 1 - x
To represent the relationships described in the word problem mathematically.
2
Multiply the entire inequality by the least common denominator, 12, to clear the fractions.
3(23x)4(x+3)>12(1x)3(2 - 3x) - 4(x + 3) > 12(1 - x)
Clearing denominators makes it easier to combine like terms and solve for xx.
3
Distribute the constants on both sides.
69x4x12>1212x6 - 9x - 4x - 12 > 12 - 12x
To remove parentheses and separate individual terms for simplification.
4
Combine like terms on the left side of the inequality.
13x6>1212x-13x - 6 > 12 - 12x
Simplifying the expressions on each side makes the inequality easier to solve.
5
Add 12x12x and 66 to both sides of the inequality to isolate variables on one side.
x>18-x > 18
To group variable terms on the left and constant terms on the right.
6
Divide both sides by 1-1 and reverse the inequality sign.
x<18x < -18
Dividing or multiplying an inequality by a negative number requires reversing the inequality sign to maintain a true statement.

Anahtar Kavram

Solving multi-step linear inequalities with rational terms and variable terms on both sides, including reversing the inequality sign when dividing by a negative number.

Alternatif Yöntem

Instead of clearing fractions first, you can distribute the division to each term (e.g., 243x4x333>1x\frac{2}{4} - \frac{3x}{4} - \frac{x}{3} - \frac{3}{3} > 1 - x), group the xx terms on one side and constants on the other using fraction arithmetic, and then solve for xx. However, clearing fractions with the LCD is generally faster and less prone to arithmetic errors.
Tahmini Süre:2m 0s
Soru 2059Soru

Two infinite geometric series, Series A and Series B, are defined as follows:

* Series A has a first term of 2x2^x and a common ratio of 12\frac{1}{2}.
* Series B has a first term of 2x+32^{x+3} and a common ratio of 34\frac{3}{4}.

If the sum of Series A and Series B is 136, what is the value of xx?

Cevabı ve açıklamayı göster

Cevap: 22

Cevap

2
The correct answer is the value 2. Substituting x=2x = 2 into the sum of Series A gives 22+1=82^{2+1} = 8. Substituting x=2x = 2 into the sum of Series B gives 22+5=1282^{2+5} = 128. The total sum is 8+128=1368 + 128 = 136, which matches the given sum.

Adım Adım Çözüm

1
Express the sum of Series A, denoted as SAS_A, using the infinite geometric series sum formula S=a11rS = \frac{a_1}{1-r}.
SA=2x11/2=2x1/2=22x=2x+1S_A = \frac{2^x}{1 - 1/2} = \frac{2^x}{1/2} = 2 \cdot 2^x = 2^{x+1}
Since the common ratio r=1/2r = 1/2 satisfies r<1|r| < 1, the infinite sum exists and can be simplified using exponent properties.
2
Express the sum of Series B, denoted as SBS_B, using the infinite geometric series sum formula.
SB=2x+313/4=2x+31/4=42x+3=222x+3=2x+5S_B = \frac{2^{x+3}}{1 - 3/4} = \frac{2^{x+3}}{1/4} = 4 \cdot 2^{x+3} = 2^2 \cdot 2^{x+3} = 2^{x+5}
Since the common ratio r=3/4r = 3/4 satisfies r<1|r| < 1, the infinite sum exists and can be simplified using exponent rules.
3
Set up the equation for the sum of both series and solve for xx.
2x+1+2x+5=136    22x+322x=136    342x=136    2x=4    x=22^{x+1} + 2^{x+5} = 136 \implies 2 \cdot 2^x + 32 \cdot 2^x = 136 \implies 34 \cdot 2^x = 136 \implies 2^x = 4 \implies x = 2
Factoring out 2x2^x from the terms allows us to isolate the exponential expression and find the value of xx.

Anahtar Kavram

Sum of an Infinite Geometric Series and Exponential Properties
Soru 2060Soru

A line in the standard (x,y)(x,y) coordinate plane passes through the point (4,1)(4, 1) and has a negative slope mm. The line and the coordinate axes bound a region in the first quadrant. If the area of this region is 88 square units, which of the following is the value of mm?

Cevabı ve açıklamayı göster

Cevap: 14-\frac{1}{4}

Cevap

14-\frac{1}{4}
The correct answer is 14-\frac{1}{4}. The line passes through (4,1)(4, 1) with slope mm. Using the point-slope formula, the equation of the line is y1=m(x4)y - 1 = m(x - 4), which simplifies to y=mx4m+1y = mx - 4m + 1. The yy-intercept is found by setting x=0x = 0, giving 14m1 - 4m. The xx-intercept is found by setting y=0y = 0, giving 4m1m\frac{4m-1}{m}. The area of the right-triangular region in the first quadrant bounded by the axes is 12(base)(height)=8\frac{1}{2} \cdot (\text{base}) \cdot (\text{height}) = 8. Substituting the intercepts, we get 12(4m1m)(14m)=8\frac{1}{2} \cdot \left(\frac{4m-1}{m}\right) \cdot (1-4m) = 8. Multiplying by 2m2m (which is negative, so we maintain positive side lengths) yields (14m)2=16m-(1-4m)^2 = 16m, which simplifies to 16m2+8m+1=016m^2 + 8m + 1 = 0. Factoring the quadratic expression gives (4m+1)2=0(4m+1)^2 = 0, which has the single solution m=14m = -\frac{1}{4}.

Adım Adım Çözüm

1
Write the equation of the line using the point-slope form with the point (4,1)(4, 1) and slope mm.
y1=m(x4)    y=mx4m+1y - 1 = m(x - 4) \implies y = mx - 4m + 1
The point-slope formula yy1=m(xx1)y - y_1 = m(x - x_1) defines any line passing through a given point with a specific slope.
2
Find the xx-intercept and yy-intercept of the line.
y-intercept=14my\text{-intercept} = 1 - 4m (when x=0x=0), and x-intercept=4m1mx\text{-intercept} = \frac{4m-1}{m} (when y=0y=0)
The intercepts represent the vertices of the right triangle formed by the line and the coordinate axes.
3
Set up the area equation for the right triangle in the first quadrant, noting that since m<0m < 0, both intercepts are positive.
Area=12baseheight    12(4m1m)(14m)=8Area = \frac{1}{2} \cdot \text{base} \cdot \text{height} \implies \frac{1}{2} \cdot \left(\frac{4m-1}{m}\right) \cdot (1-4m) = 8
The area of the region bounded by the axes and the line is a right triangle whose legs are the intercepts.
4
Solve the algebraic equation for mm.
(4m1)(14m)=16m    16m2+8m+1=0    (4m+1)2=0    m=14(4m-1)(1-4m) = 16m \implies 16m^2 + 8m + 1 = 0 \implies (4m+1)^2 = 0 \implies m = -\frac{1}{4}
Multiplying both sides by 2m2m and expanding the terms leads to a quadratic equation in terms of mm, which resolves to a single real root.

Anahtar Kavram

Using linear equation forms and coordinate geometry to represent boundary lines and compute bounded areas.

Alternatif Yöntem

Instead of using the point-slope form, write the line in intercept form: xa+yb=1\frac{x}{a} + \frac{y}{b} = 1, where aa and bb are the xx- and yy-intercepts. The area of the region is 12ab=8    ab=16    b=16a\frac{1}{2}ab = 8 \implies ab = 16 \implies b = \frac{16}{a}. Substitute this back into the intercept form to get xa+y16/a=1    xa+ay16=1\frac{x}{a} + \frac{y}{16/a} = 1 \implies \frac{x}{a} + \frac{ay}{16} = 1. Since the line passes through (4,1)(4, 1), substitute these coordinates: 4a+a(1)16=1\frac{4}{a} + \frac{a(1)}{16} = 1. Multiply the entire equation by 16a16a to clear the denominators: 64+a2=16a    a216a+64=0    (a8)2=0    a=864 + a^2 = 16a \implies a^2 - 16a + 64 = 0 \implies (a-8)^2 = 0 \implies a = 8. Since a=8a = 8, the yy-intercept is b=168=2b = \frac{16}{8} = 2. Using the intercepts (8,0)(8, 0) and (0,2)(0, 2), the slope is m=2008=28=14m = \frac{2 - 0}{0 - 8} = -\frac{2}{8} = -\frac{1}{4}.
Tahmini Süre:2m 30s
ÖncekiSayfa 103 / 278Sonraki
Tüm alıştırma soruları — ACT | Examkin