Tüm alıştırma soruları

5556 soru

Soru 1981Soru

A manufacturing company determines that its weekly profit from producing xx batches of a product is constrained by resource availability. To meet these resource constraints, the number of batches xx must satisfy the inequality:

5(6x)33(x+2)4>2x11\frac{5(6 - x)}{3} - \frac{3(x + 2)}{4} > 2x - 11

What is the greatest number of whole batches the company can produce while satisfying this constraint?

Cevabı ve açıklamayı göster

Cevap: 4

Cevap

The greatest number of whole batches the company can produce is 4.
Solving the inequality yields x<234534.415x < \frac{234}{53} \approx 4.415. The greatest integer value that satisfies this condition is 4.

Adım Adım Çözüm

1
Multiply both sides of the inequality by the least common multiple of the denominators, which is 12.
20(6x)9(x+2)>24x13220(6 - x) - 9(x + 2) > 24x - 132
Multiplying by 12 eliminates the fractions, making the inequality easier to solve.
2
Distribute the constants on the left side of the inequality.
12020x9x18>24x132120 - 20x - 9x - 18 > 24x - 132
Distributing 20 to (6x)(6 - x) yields 12020x120 - 20x, and distributing 9-9 to (x+2)(x + 2) yields 9x18-9x - 18.
3
Combine like terms on the left side of the inequality.
10229x>24x132102 - 29x > 24x - 132
Combining 12018120 - 18 gives 102102, and combining 20x9x-20x - 9x gives 29x-29x.
4
Subtract 24x24x from both sides to group the variable terms on the left side.
10253x>132102 - 53x > -132
This groups all terms containing the variable xx on one side of the inequality.
5
Subtract 102 from both sides to isolate the variable term.
53x>234-53x > -234
This isolates the term containing xx on the left side of the inequality.
6
Divide both sides by 53-53 and reverse the inequality sign.
x<23453x < \frac{234}{53}
Dividing by a negative number requires reversing the direction of the inequality sign.
7
Evaluate the fraction as a decimal and determine the greatest integer value of xx that satisfies the inequality.
x<4.415x < 4.415, which means the greatest integer is 4.
Since the company must produce a whole number of batches, we find the largest integer less than 4.415.

Anahtar Kavram

Solving multi-step linear inequalities involving fractional coefficients, distributing negative numbers, and reversing the inequality sign when multiplying or dividing by a negative number.

Alternatif Yöntem

Instead of solving algebraically, you can test integer values for xx directly in the inequality. Testing x=4x = 4 gives 103184=3.334.5=1.17\frac{10}{3} - \frac{18}{4} = 3.33 - 4.5 = -1.17, which is greater than 2(4)11=32(4) - 11 = -3 (True). Testing x=5x = 5 gives 53214=1.675.25=3.58\frac{5}{3} - \frac{21}{4} = 1.67 - 5.25 = -3.58, which is not greater than 2(5)11=12(5) - 11 = -1 (False). This confirms 4 is the largest integer satisfying the inequality.
Tahmini Süre:2m 30s
Soru 1982Soru

Which of the following is the completely factored form of the expression 3x(x2)212x3x(x - 2)^2 - 12x?

Cevabı ve açıklamayı göster

Cevap: 3x2(x4)3x^2(x - 4)

Cevap

The completely factored form of the expression is 3x2(x4)3x^2(x - 4).
The correct answer is 3x2(x4)3x^2(x-4). Factoring out the greatest common factor 3x3x from the terms 3x(x2)23x(x-2)^2 and 12x-12x gives 3x[(x2)24]3x[(x-2)^2-4]. The expression within the brackets is a difference of squares that can be factored as [(x2)2][(x2)+2][(x-2)-2][(x-2)+2], which simplifies to x(x4)x(x-4). Multiplying this by the GCF 3x3x yields 3x2(x4)3x^2(x-4).

Adım Adım Çözüm

1
Factor out the greatest common factor (GCF), 3x3x, from both terms of the expression 3x(x2)212x3x(x - 2)^2 - 12x.
3x[(x2)24]3x[(x - 2)^2 - 4]
Both terms 3x(x2)23x(x-2)^2 and 12x12x share the common factors 33 and xx.
2
Factor the difference of squares inside the bracket, (x2)24(x-2)^2 - 4, using the formula a2b2=(ab)(a+b)a^2 - b^2 = (a-b)(a+b) where a=x2a = x-2 and b=2b = 2.
[(x2)2][(x2)+2]=(x4)(x)[(x-2)-2][(x-2)+2] = (x-4)(x)
Since 4=224 = 2^2, the terms inside the brackets form a difference of squares.
3
Combine the factored parts and simplify the expression by multiplying the variable terms.
3xx(x4)=3x2(x4)3x \cdot x(x-4) = 3x^2(x-4)
Multiplying 3x3x by xx requires adding their exponents (1+1=21 + 1 = 2).

Anahtar Kavram

Factoring polynomials using the greatest common factor (GCF) and difference of squares.
Soru 1983Soru

When the expression 4x(x2y)(2x3y)2+5y(2xy)4x(x - 2y) - (2x - 3y)^2 + 5y(2x - y) is simplified to the form Ax2+Bxy+Cy2Ax^2 + Bxy + Cy^2, where AA, BB, and CC are constants, what is the value of BB?

Cevabı ve açıklamayı göster

Cevap: 14

Cevap

The value of the coefficient BB is 14.
Expanding the entire expression yields 4x28xy4x2+12xy9y2+10xy5y24x^2 - 8xy - 4x^2 + 12xy - 9y^2 + 10xy - 5y^2. Grouping and combining the xyxy terms gives (8+12+10)xy=14xy(-8 + 12 + 10)xy = 14xy. Therefore, the coefficient BB is 14.

Adım Adım Çözüm

1
Expand the first term
4x28xy4x^2 - 8xy
Distribute 4x4x to both terms inside the parentheses: 4x(x)4x(2y)=4x28xy4x(x) - 4x(2y) = 4x^2 - 8xy.
2
Expand the squared binomial and apply the negative sign
4x2+12xy9y2-4x^2 + 12xy - 9y^2
Use the binomial expansion formula (2x3y)2=4x212xy+9y2(2x - 3y)^2 = 4x^2 - 12xy + 9y^2, then multiply each term by 1-1.
3
Expand the third term
10xy5y210xy - 5y^2
Distribute 5y5y to both terms inside the parentheses: 5y(2x)5y(y)=10xy5y25y(2x) - 5y(y) = 10xy - 5y^2.
4
Combine the coefficients of the like terms
0x2+14xy14y20x^2 + 14xy - 14y^2
Sum the coefficients for each corresponding variable group: (44)x2+(8+12+10)xy+(95)y2(4 - 4)x^2 + (-8 + 12 + 10)xy + (-9 - 5)y^2.

Anahtar Kavram

Simplifying Algebraic Expressions and Combining Like Terms
Soru 1984Soru

In the standard (x,y)(x, y) coordinate plane, the line defined by the equation 3x4y=k3x - 4y = k is tangent to the circle defined by the equation x2+y22x4y=4x^2 + y^2 - 2x - 4y = 4. If k>0k > 0, what is the value of kk?

Cevabı ve açıklamayı göster

Cevap: 10

Cevap

10
The correct answer is 10. Completing the square for the circle's equation gives (x1)2+(y2)2=9(x - 1)^2 + (y - 2)^2 = 9, showing the center is (1,2)(1, 2) and the radius is 33. The distance from (1,2)(1, 2) to the line 3x4yk=03x - 4y - k = 0 is 3(1)4(2)k32+(4)2=k+55\frac{|3(1) - 4(2) - k|}{\sqrt{3^2 + (-4)^2}} = \frac{|k + 5|}{5}. For tangency, this distance must equal the radius: k+55=3\frac{|k + 5|}{5} = 3, which gives k+5=15|k + 5| = 15. Solving this absolute value equation gives k=10k = 10 or k=20k = -20. Since kk must be positive, the value is 10.

Adım Adım Çözüm

1
Complete the square for the circle's equation x2+y22x4y=4x^2 + y^2 - 2x - 4y = 4.
(x1)2+(y2)2=9(x - 1)^2 + (y - 2)^2 = 9, which represents a circle with center (1,2)(1, 2) and radius R=3R = 3.
To find the center and radius of the circle, which are needed to use the distance formula.
2
Express the distance dd from the center (1,2)(1, 2) to the line 3x4yk=03x - 4y - k = 0 using the formula d=Ax0+By0+CA2+B2d = \frac{|Ax_0 + By_0 + C|}{\sqrt{A^2 + B^2}}.
d=3(1)4(2)k32+(4)2=5k5=k+55d = \frac{|3(1) - 4(2) - k|}{\sqrt{3^2 + (-4)^2}} = \frac{|-5 - k|}{5} = \frac{|k + 5|}{5}.
A line is tangent to a circle if and only if the distance from the center of the circle to the line equals the radius.
3
Set the distance equal to the radius (33) and solve for kk.
k+55=3k+5=15\frac{|k + 5|}{5} = 3 \Rightarrow |k + 5| = 15, which yields k+5=15k=10k + 5 = 15 \Rightarrow k = 10, or k+5=15k=20k + 5 = -15 \Rightarrow k = -20.
To find the values of kk that make the line tangent to the circle.
4
Select the positive value of kk.
k=10k = 10.
The problem specifies that k>0k > 0.

Anahtar Kavram

Systems of Linear and Non-Linear Equations
Tahmini Süre:2m 30s
Soru 1985Soru

For a certain geometric sequence, the first term is 232^3 and the common ratio is 222^2. Which of the following expressions represents the 3rd term of this sequence?

Cevabı ve açıklamayı göster

Cevap: 272^7

Cevap

The 3rd term of the sequence is 272^7.
The correct answer is 272^7. The nn-th term of a geometric sequence is given by an=a1rn1a_n = a_1 \cdot r^{n-1}. For a first term a1=23a_1 = 2^3 and a common ratio r=22r = 2^2, the 3rd term is a3=23(22)31=2324a_3 = 2^3 \cdot (2^2)^{3-1} = 2^3 \cdot 2^4. Applying the exponent addition rule for multiplying bases of the same value yields 23+4=272^{3+4} = 2^7.

Adım Adım Çözüm

1
Identify the formula for the nn-th term of a geometric sequence.
an=a1rn1a_n = a_1 \cdot r^{n-1}
To find any specific term in a geometric sequence, the general term formula is used.
2
Substitute the given values (a1=23a_1 = 2^3, r=22r = 2^2, and n=3n = 3) into the formula.
a3=23(22)31=23(22)2a_3 = 2^3 \cdot (2^2)^{3-1} = 2^3 \cdot (2^2)^2
This sets up the calculation for the 3rd term of the sequence.
3
Simplify the expression using exponent rules: first compute (22)2(2^2)^2, then multiply by 232^3.
a3=2324=23+4=27a_3 = 2^3 \cdot 2^4 = 2^{3+4} = 2^7
Power of a power rule states (xa)b=xab(x^a)^b = x^{ab}, and product of powers rule states xaxb=xa+bx^a \cdot x^b = x^{a+b}.

Anahtar Kavram

Finding a specific term of a geometric sequence using the general term formula an=a1rn1a_n = a_1 \cdot r^{n-1} and applying laws of exponents.
Tahmini Süre:45s
Soru 1986Soru

The functions ff and gg are defined for all real numbers by f(x)=2x5f(x) = 2x - 5 and g(x)=(x+3)2g(x) = (x + 3)^2. What is the value of f(g(1))f(g(-1))?

Cevabı ve açıklamayı göster

Cevap: 3

Cevap

3
To evaluate the composite function f(g(1))f(g(-1)), first evaluate the inner function g(1)=(1+3)2=4g(-1) = (-1 + 3)^2 = 4. Then, substitute this result into the outer function to get f(4)=2(4)5=3f(4) = 2(4) - 5 = 3.

Adım Adım Çözüm

1
Evaluate the inner function g(x)g(x) at x=1x = -1.
g(1)=4g(-1) = 4
In the composition f(g(1))f(g(-1)), the inner function must be evaluated first. Substituting 1-1 into g(x)=(x+3)2g(x) = (x + 3)^2 gives g(1)=(1+3)2=22=4g(-1) = (-1 + 3)^2 = 2^2 = 4.
2
Evaluate the outer function f(x)f(x) at the output of the inner function.
f(4)=3f(4) = 3
Substitute the output g(1)=4g(-1) = 4 into f(x)=2x5f(x) = 2x - 5, which yields f(4)=2(4)5=85=3f(4) = 2(4) - 5 = 8 - 5 = 3.

Anahtar Kavram

Function Composition and Evaluation
Tahmini Süre:1m 0s
Soru 1987Soru
A clothing boutique sells two types of shirts: t-shirts and polo shirts. The number of shirts sold at the boutique's two locations, Downtown and Uptown, on a weekend is represented by matrix SS:
S = \begin{pmatrix} 40 & 30 \\ 50 & 20 \\end{pmatrix}
where the rows represent the locations (Downtown and Uptown, respectively) and the columns represent the shirt types (t-shirts and polo shirts, respectively).
The selling price and the production cost per shirt (in dollars) are represented by matrix CC:
C = \begin{pmatrix} 15 & 6 \\ 25 & 10 \\end{pmatrix}
where the rows represent the shirt types (t-shirts and polo shirts, respectively) and the columns represent the selling price and production cost, respectively.

Which of the following matrices represents the total selling revenue and total production cost for the two locations?

Cevabı ve açıklamayı göster

Cevap: \begin{pmatrix} 1350 & 540 \\ 1250 & 500 \\end{pmatrix}

Cevap

The matrix representing the total selling revenue and total production cost for the two locations is the matrix with top row 1350 and 540, and bottom row 1250 and 500.
The correct matrix is obtained by multiplying the sales matrix SS by the price/cost matrix CC. Standard matrix multiplication pairs the quantity of each shirt type sold at each store with its respective selling price and production cost, yielding the correct total revenue and total production cost for both locations.

Adım Adım Çözüm

1
Identify the dimensions and layout of the sales matrix SS and the price/cost matrix CC.
Matrix SS is a 2×22 \times 2 matrix representing sales. Matrix CC is a 2×22 \times 2 matrix representing price and cost. The product SCSC is defined because the number of columns in SS (2) equals the number of rows in CC (2).
Before multiplying, we must verify that the dimensions are compatible and that the product yields the desired real-world quantities.
2
Calculate the entries for the first row of the resulting matrix SCSC (Downtown location) by taking the dot product of the first row of SS with the columns of CC.
Revenue (Row 1, Column 1): 40×15+30×25=600+750=135040 \times 15 + 30 \times 25 = 600 + 750 = 1350.
Cost (Row 1, Column 2): 40×6+30×10=240+300=54040 \times 6 + 30 \times 10 = 240 + 300 = 540.
This yields the total revenue and production cost for the Downtown location by combining sales and prices/costs for both shirt types.
3
Calculate the entries for the second row of the resulting matrix SCSC (Uptown location) by taking the dot product of the second row of SS with the columns of CC.
Revenue (Row 2, Column 1): 50×15+20×25=750+500=125050 \times 15 + 20 \times 25 = 750 + 500 = 1250.
Cost (Row 2, Column 2): 50×6+20×10=300+200=50050 \times 6 + 20 \times 10 = 300 + 200 = 500.
This yields the total revenue and production cost for the Uptown location.

Anahtar Kavram

Matrix multiplication
Soru 1988Soru

An infinite geometric series of positive terms has a sum of 99. The sum of the first two terms of the series is 88. What is the first term of this series?

Cevabı ve açıklamayı göster

Cevap: 6

Cevap

The first term of the series is 6.
To find the first term of the geometric series, we set up a system of equations using the formulas for the sum of the first two terms, S2=a(1+r)=8S_2 = a(1+r) = 8, and the sum of an infinite geometric series, S=a1r=9S_\infty = \frac{a}{1-r} = 9. Expressing the first term as a=9(1r)a = 9(1-r) and substituting this into the first equation yields 9(1r)(1+r)=89(1-r)(1+r) = 8, which simplifies to 9(1r2)=89(1-r^2) = 8. Solving for the ratio yields r2=19r^2 = \frac{1}{9}, which means r=13r = \frac{1}{3} since all terms must be positive. Substituting r=13r = \frac{1}{3} back into a=9(1r)a = 9(1-r) gives the first term as 66.

Adım Adım Çözüm

1
Define variables and identify the given formulas.
Let the first term of the geometric series be aa and the common ratio be rr. Since the series has positive terms, we require a>0a > 0 and 0<r<10 < r < 1.
This sets up the system of equations using standard geometric sequence notation.
2
Translate the given problem conditions into algebraic equations.
Equation 1 (sum of the first two terms): S2=a+ar=a(1+r)=8S_2 = a + ar = a(1+r) = 8.
Equation 2 (sum to infinity): S=a1r=9S_\infty = \frac{a}{1-r} = 9.
We must express the two mathematical relationships given in the problem statement.
3
Express the first term aa in terms of the common ratio rr using Equation 2.
a=9(1r)a = 9(1-r)
This allows for substitution into Equation 1 to solve for rr.
4
Substitute the expression for aa into Equation 1 and simplify.
9(1r)(1+r)=8    9(1r2)=8    99r2=89(1-r)(1+r) = 8 \implies 9(1-r^2) = 8 \implies 9 - 9r^2 = 8.
Substituting simplifies the system from two variables to a single quadratic variable in terms of rr.
5
Solve the quadratic equation for rr.
9r2=1    r2=19    r=139r^2 = 1 \implies r^2 = \frac{1}{9} \implies r = \frac{1}{3} (since r>0r > 0).
Finding the value of the common ratio is the final step before calculating the first term.
6
Substitute the value of rr back into the expression for aa.
a=9(113)=9(23)=6a = 9\left(1 - \frac{1}{3}\right) = 9\left(\frac{2}{3}\right) = 6.
This yields the value of the first term aa to complete the problem.

Anahtar Kavram

Solving systems of non-linear equations using geometric sequence term and infinite sum formulas.

Alternatif Yöntem

Instead of substituting a=9(1r)a = 9(1-r) into a(1+r)=8a(1+r) = 8, we can divide the two equations: a(1+r)a/(1r)=89    (1r)(1+r)=89    1r2=89\frac{a(1+r)}{a/(1-r)} = \frac{8}{9} \implies (1-r)(1+r) = \frac{8}{9} \implies 1 - r^2 = \frac{8}{9}. This directly yields r2=19r^2 = \frac{1}{9} without needing to isolate aa first.
Tahmini Süre:2m 0s
Soru 1989Soru

For a real number xx, 12\frac{1}{2} minus 23\frac{2}{3} of xx is greater than 56\frac{5}{6}. Which of the following is the complete set of solutions for xx?

Cevabı ve açıklamayı göster

Cevap: x<12x < -\frac{1}{2}

Cevap

x<12x < -\frac{1}{2}
Subtracting 12\frac{1}{2} from both sides of the inequality 1223x>56\frac{1}{2} - \frac{2}{3}x > \frac{5}{6} gives 23x>26-\frac{2}{3}x > \frac{2}{6}, which simplifies to 23x>13-\frac{2}{3}x > \frac{1}{3}. Multiplying both sides by the negative fraction 32-\frac{3}{2} isolates xx on the left and reverses the inequality sign from greater than (>>) to less than (<<). Performing the multiplication on the right yields 13(32)=12\frac{1}{3} \cdot \left(-\frac{3}{2}\right) = -\frac{1}{2}. Thus, the solution set is x<12x < -\frac{1}{2}.

Adım Adım Çözüm

1
Translate the verbal description into an algebraic inequality.
1223x>56\frac{1}{2} - \frac{2}{3}x > \frac{5}{6}
The phrase '12\frac{1}{2} minus 23\frac{2}{3} of xx' represents the expression 1223x\frac{1}{2} - \frac{2}{3}x, and 'is greater than' translates to the inequality symbol >>.
2
Subtract 12\frac{1}{2} from both sides of the inequality.
23x>13-\frac{2}{3}x > \frac{1}{3}
To isolate the variable term on the left, we subtract 12\frac{1}{2} (which is equivalent to 36\frac{3}{6}) from 56\frac{5}{6} to get 26=13\frac{2}{6} = \frac{1}{3}.
3
Multiply both sides of the inequality by 32-\frac{3}{2} and reverse the inequality sign.
x<12x < -\frac{1}{2}
Multiplying both sides of an inequality by a negative number requires reversing the direction of the inequality sign from >> to << to keep the inequality true.

Anahtar Kavram

Solving multi-step linear inequalities involving multiplication or division by a negative number.
Soru 1990Soru

Consider the function ff defined on the domain [23,)[\frac{2}{3}, \infty) by the equation f(x)=2+3x2f(x) = 2 + \sqrt{3x - 2}. If f1f^{-1} represents the inverse of ff, what is the only real value of xx for which f(x)=f1(x)f(x) = f^{-1}(x)?

Cevabı ve açıklamayı göster

Cevap: 6

Cevap

The only real value of xx for which f(x)=f1(x)f(x) = f^{-1}(x) is 6.
For a strictly increasing function, the intersection of f(x)f(x) and f1(x)f^{-1}(x) must occur on the line y=xy = x. Equating f(x)=xf(x) = x gives 2+3x2=x2 + \sqrt{3x - 2} = x. Isolating the radical term yields 3x2=x2\sqrt{3x - 2} = x - 2. Squaring both sides produces 3x2=x24x+43x - 2 = x^2 - 4x + 4, which simplifies to the quadratic equation x27x+6=0x^2 - 7x + 6 = 0. Factoring this equation gives (x6)(x1)=0(x - 6)(x - 1) = 0, yielding the solutions x=6x = 6 and x=1x = 1. Substituting these back into the original equation shows that x=6x = 6 is a valid solution (2+16=62 + \sqrt{16} = 6), whereas x=1x = 1 is extraneous because it results in 2+1=312 + 1 = 3 \neq 1. Furthermore, the domain of f1f^{-1} is the range of ff, which is [2,)[2, \infty), meaning f1(1)f^{-1}(1) is undefined. Thus, the only real solution is 6.

Adım Adım Çözüm

1
Equate the function to xx using properties of increasing functions and their inverses.
Since f(x)f(x) is strictly increasing on its domain [23,)[\frac{2}{3}, \infty), the graph of f(x)f(x) and the graph of its inverse f1(x)f^{-1}(x) can only intersect on the line of symmetry y=xy = x. Therefore, the equation f(x)=f1(x)f(x) = f^{-1}(x) is equivalent to f(x)=xf(x) = x.
This simplifies the relation by eliminating the need to solve a high-degree polynomial equation derived from direct composition or substitution.
2
Set up the equation f(x)=xf(x) = x and isolate the radical term.
2+3x2=x    3x2=x22 + \sqrt{3x - 2} = x \implies \sqrt{3x - 2} = x - 2
Isolating the square root term is a necessary prerequisite step before squaring both sides.
3
Square both sides and rewrite the equation as a standard quadratic equation.
3x2=(x2)2    3x2=x24x+4    x27x+6=03x - 2 = (x - 2)^2 \implies 3x - 2 = x^2 - 4x + 4 \implies x^2 - 7x + 6 = 0
Squaring eliminates the radical to yield a standard quadratic equation that can be solved analytically.
4
Solve the quadratic equation by factoring.
(x6)(x1)=0    x=6 or x=1(x - 6)(x - 1) = 0 \implies x = 6 \text{ or } x = 1
Factoring the quadratic trinomial yields the two candidate values for xx.
5
Check the candidate solutions in the original equation to eliminate extraneous roots.
For x=1x = 1: 2+3(1)2=312 + \sqrt{3(1)-2} = 3 \neq 1 (extraneous). For x=6x = 6: 2+3(6)2=2+4=62 + \sqrt{3(6)-2} = 2 + 4 = 6 (valid). Also, the domain of f1f^{-1} is the range of ff, which is [2,)[2, \infty), thus excluding x=1x = 1.
Squaring both sides can introduce extraneous roots. We must verify that the solutions satisfy the original radical equation and fall within the domains of both ff and f1f^{-1}.

Anahtar Kavram

Applying the symmetry of inverse functions about the line y=xy=x to solve composition-based equations, while rigorously accounting for domain restrictions and extraneous roots.

Alternatif Yöntem

Find the algebraic formula for f1(x)f^{-1}(x) by setting y=2+3x2y = 2 + \sqrt{3x-2}. Subtracting 2 and squaring both sides gives (y2)2=3x2(y - 2)^2 = 3x - 2 for y2y \geq 2. Solving for xx yields f1(x)=(x2)2+23f^{-1}(x) = \frac{(x - 2)^2 + 2}{3} for x2x \geq 2. Equating f(x)=f1(x)f(x) = f^{-1}(x) results in 2+3x2=(x2)2+232 + \sqrt{3x - 2} = \frac{(x - 2)^2 + 2}{3}. Multiplying by 3 and isolating the radical term gives 33x2=x24x3\sqrt{3x - 2} = x^2 - 4x. Squaring both sides results in a fourth-degree polynomial equation: 9(3x2)=(x24x)2    x48x3+16x227x+18=09(3x - 2) = (x^2 - 4x)^2 \implies x^4 - 8x^3 + 16x^2 - 27x + 18 = 0. This factors into (x6)(x1)(x2x+3)=0(x - 6)(x - 1)(x^2 - x + 3) = 0. Since the domain of f1(x)f^{-1}(x) is restricted to x2x \geq 2, the root x=1x = 1 is rejected, and the quadratic factor x2x+3=0x^2 - x + 3 = 0 has no real roots, leaving x=6x = 6 as the unique real solution.
Tahmini Süre:3m 0s
Soru 1991Soru

A right triangle has an area of 66 square units. The lengths of its legs, aa and bb, satisfy the quadratic equation a22.75ab+1.5b2=0a^2 - 2.75ab + 1.5b^2 = 0. If the length of the hypotenuse is an integer, what is the perimeter of the triangle?

Cevabı ve açıklamayı göster

Cevap: 12

Cevap

The perimeter of the triangle is 12.
The correct answer is 12. By solving the quadratic relationship between the legs, we find two possible ratios: one where one leg is twice the other, and one where one leg is 0.75 times the other. Using the area of 6, the first case yields non-integer side lengths, while the second case yields legs of length 3 and 4. This results in an integer hypotenuse of 5, giving a perimeter of 3 + 4 + 5 = 12.

Adım Adım Çözüm

1
Express the relation a22.75ab+1.5b2=0a^2 - 2.75ab + 1.5b^2 = 0 as a quadratic in terms of the ratio r=abr = \frac{a}{b}.
The equation becomes r22.75r+1.5=0r^2 - 2.75r + 1.5 = 0.
To find the relationship between the two legs of the triangle by solving for their ratio.
2
Apply the quadratic formula to solve for rr.
r=2r = 2 or r=0.75r = 0.75, meaning either a=2ba = 2b or a=0.75ba = 0.75b.
To determine the two possible linear relationships between the legs of the right triangle.
3
Substitute each ratio case into the area formula Area=12ab=6\text{Area} = \frac{1}{2}ab = 6, which simplifies to ab=12ab = 12.
For a=2ba = 2b, we get b=6b = \sqrt{6} and a=26a = 2\sqrt{6}. For a=0.75ba = 0.75b, we get b=4b = 4 and a=3a = 3.
To calculate the actual leg lengths for both geometric cases.
4
Calculate the hypotenuse c=a2+b2c = \sqrt{a^2 + b^2} for both cases to check which yields an integer value.
The first case yields c=30c = \sqrt{30}, which is not an integer. The second case yields c=32+42=5c = \sqrt{3^2 + 4^2} = 5, which is an integer.
To satisfy the constraint that the hypotenuse must be an integer, identifying the correct leg lengths as 33 and 44.
5
Calculate the perimeter of the triangle for the valid case.
The perimeter is 3+4+5=123 + 4 + 5 = 12.
To find the final requested value.

Anahtar Kavram

Solving quadratic relationships and applying the quadratic formula in geometric constraints.
Tahmini Süre:3m 0s
Soru 1992Soru

If 3x+19x=3\sqrt{3x + 19} - x = 3, what is the value of xx?

Cevabı ve açıklamayı göster

Cevap: 2

Cevap

The value of xx is 2.
To solve the equation, isolate the radical to obtain 3x+19=x+3\sqrt{3x + 19} = x + 3. Squaring both sides yields 3x+19=x2+6x+93x + 19 = x^2 + 6x + 9. Rearranging terms results in the quadratic equation x2+3x10=0x^2 + 3x - 10 = 0, which factors into (x+5)(x2)=0(x + 5)(x - 2) = 0. The potential solutions are x=2x = 2 and x=5x = -5. Testing these in the original equation shows that 22 is a valid solution because 3(2)+192=3\sqrt{3(2) + 19} - 2 = 3. Testing 5-5 results in 3(5)+19(5)=7\sqrt{3(-5) + 19} - (-5) = 7, which does not equal 33. Thus, the only real solution is 22.

Adım Adım Çözüm

1
Isolate the radical expression on one side of the equation.
3x+19=x+3\sqrt{3x + 19} = x + 3
Isolating the radical allows us to eliminate it by squaring both sides.
2
Square both sides of the equation.
3x+19=x2+6x+93x + 19 = x^2 + 6x + 9
Squaring a square root removes the radical. Remember to expand (x+3)2(x+3)^2 correctly as x2+6x+9x^2 + 6x + 9.
3
Rearrange the terms into standard quadratic form, ax2+bx+c=0ax^2 + bx + c = 0.
x2+3x10=0x^2 + 3x - 10 = 0
Moving all terms to one side sets up the quadratic equation for factoring.
4
Factor the quadratic expression.
(x+5)(x2)=0(x + 5)(x - 2) = 0
Factoring allows us to find the potential values of xx by setting each factor to zero.
5
Solve for the potential values of xx.
x=5x = -5 or x=2x = 2
Setting x+5=0x + 5 = 0 gives x=5x = -5, and setting x2=0x - 2 = 0 gives x=2x = 2.
6
Check both potential solutions in the original equation to identify any extraneous solutions.
For x=2x = 2: 3(2)+192=252=52=3\sqrt{3(2) + 19} - 2 = \sqrt{25} - 2 = 5 - 2 = 3 (valid). For x=5x = -5: 3(5)+19(5)=4+5=2+5=73\sqrt{3(-5) + 19} - (-5) = \sqrt{4} + 5 = 2 + 5 = 7 \neq 3 (extraneous).
Squaring both sides of an equation can introduce extraneous solutions that do not satisfy the original equation.

Anahtar Kavram

Solving radical equations and checking for extraneous solutions.
Soru 1993Soru

Let matrix X=[5321]X = \begin{bmatrix} 5 & -3 \\ 2 & 1 \end{bmatrix} and matrix Y=[1423]Y = \begin{bmatrix} 1 & 4 \\ -2 & 3 \end{bmatrix}. If Z=XYZ = X - Y, what is the value of the element in the first row and second column of ZZ?

Cevabı ve açıklamayı göster

Cevap: -7

Cevap

The correct answer is 7-7.
To find the element in the first row and second column of matrix Z=XYZ = X - Y, we subtract the element in the first row and second column of matrix YY from the corresponding element in matrix XX. The element in the first row and second column of XX is 3-3, and the element in the first row and second column of YY is 44. Subtracting these values gives 34=7-3 - 4 = -7.

Adım Adım Çözüm

1
Identify the elements in the first row and second column for both matrices.
x1,2=3x_{1,2} = -3 and y1,2=4y_{1,2} = 4
To find the element in the first row and second column of the resulting matrix ZZ, we must use the corresponding elements from matrices XX and YY.
2
Subtract the element of YY from the element of XX.
34=7-3 - 4 = -7
Since Z=XYZ = X - Y, each element zi,jz_{i,j} of the resulting matrix is calculated as xi,jyi,jx_{i,j} - y_{i,j}.

Anahtar Kavram

Matrix Subtraction
Soru 1994Soru

What is the sum of the two solutions to the quadratic equation 2x27x4=02x^2 - 7x - 4 = 0?

Cevabı ve açıklamayı göster

Cevap: 3.5

Cevap

The sum of the solutions is 3.53.5.
The sum of the solutions of the quadratic equation 2x27x4=02x^2 - 7x - 4 = 0 is 3.53.5. According to Vieta's formulas, the sum of the roots of a quadratic equation in the form ax2+bx+c=0ax^2 + bx + c = 0 is given by ba-\frac{b}{a}. Here, a=2a = 2 and b=7b = -7, so the sum is 72=3.5-\frac{-7}{2} = 3.5. Alternatively, solving the equation using the quadratic formula yields the roots 44 and 0.5-0.5, which sum to 3.53.5.

Adım Adım Çözüm

1
Identify the coefficients from the quadratic equation 2x27x4=02x^2 - 7x - 4 = 0.
a=2a = 2, b=7b = -7, and c=4c = -4.
A quadratic equation in standard form is written as ax2+bx+c=0ax^2 + bx + c = 0.
2
Apply the sum of roots formula ba-\frac{b}{a}.
Sum =72=3.5= -\frac{-7}{2} = 3.5.
By Vieta's formulas, the sum of the roots of ax2+bx+c=0ax^2 + bx + c = 0 is ba-\frac{b}{a}.

Anahtar Kavram

Sum of roots of a quadratic equation using Vieta's formulas

Alternatif Yöntem

Solve the quadratic equation by factoring or using the quadratic formula. Factoring 2x27x4=02x^2 - 7x - 4 = 0 yields (2x+1)(x4)=0(2x + 1)(x - 4) = 0, which gives solutions x=0.5x = -0.5 and x=4x = 4. Adding these solutions together gives 0.5+4=3.5-0.5 + 4 = 3.5.
Tahmini Süre:1m 0s
Soru 1995Soru

The polynomial P(x)P(x) is defined by P(x)=(2x23x+5)24x(x32x27x+1)P(x) = (2x^2 - 3x + 5)^2 - 4x(x^3 - 2x^2 - 7x + 1). When P(x)P(x) is written in standard form, what is the coefficient of the x2x^2 term?

Cevabı ve açıklamayı göster

Cevap: 57

Cevap

The coefficient of the x2x^2 term is 57.
Expanding (2x23x+5)2(2x^2 - 3x + 5)^2 yields (2x23x+5)(2x23x+5)=4x412x3+29x230x+25(2x^2 - 3x + 5)(2x^2 - 3x + 5) = 4x^4 - 12x^3 + 29x^2 - 30x + 25. Distributing the 4x-4x term yields 4x(x32x27x+1)=4x4+8x3+28x24x-4x(x^3 - 2x^2 - 7x + 1) = -4x^4 + 8x^3 + 28x^2 - 4x. Combining the x2x^2 terms from both expressions gives 29x2+28x2=57x229x^2 + 28x^2 = 57x^2. Thus, the coefficient of the x2x^2 term is 57.

Adım Adım Çözüm

1
Expand the squared trinomial (2x23x+5)2(2x^2 - 3x + 5)^2
4x412x3+29x230x+254x^4 - 12x^3 + 29x^2 - 30x + 25
Expanding the first part of the expression by multiplying the trinomial by itself.
2
Distribute the term 4x-4x to the trinomial (x32x27x+1)(x^3 - 2x^2 - 7x + 1)
4x4+8x3+28x24x-4x^4 + 8x^3 + 28x^2 - 4x
Expanding the second part of the polynomial expression while distributing the negative sign to all terms.
3
Combine the expanded expressions and isolate the x2x^2 terms
29x2+28x2=57x229x^2 + 28x^2 = 57x^2
Adding the coefficients of the terms of degree 2 to find the combined coefficient.

Anahtar Kavram

Operations on Polynomials
Soru 1996Soru
For all non-zero real numbers yy, the expression
(y3)2(y4)ay5\frac{(y^3)^2 \cdot (y^{-4})^a}{y^5}
is equivalent to y7y^{-7}. What is the value of aa?
Cevabı ve açıklamayı göster

Cevap: 22

Cevap

The correct value of aa is 2.
Applying the exponent rules systematically allows us to simplify the expression. First, (y3)2(y^3)^2 becomes y6y^6 and (y4)a(y^{-4})^a becomes y4ay^{-4a} using the power of a power rule. Second, we combine the terms in the numerator using the product rule to get y64ay^{6-4a}. Third, we divide by y5y^5 using the quotient rule to obtain y64a5=y14ay^{6-4a-5} = y^{1-4a}. Setting this equal to the target expression y7y^{-7} gives the equation 14a=71-4a = -7. Solving for aa gives 4a=8-4a = -8, which simplifies to 22.

Adım Adım Çözüm

1
Apply the power of a power rule, (xm)n=xmn(x^m)^n = x^{mn}, to the exponential terms in the numerator.
(y3)2=y6(y^3)^2 = y^6 and (y4)a=y4a(y^{-4})^a = y^{-4a}
This simplifies nested exponent terms into single base terms.
2
Apply the product rule of exponents, xmxn=xm+nx^m \cdot x^n = x^{m+n}, to combine the numerator terms.
y6y4a=y64ay^6 \cdot y^{-4a} = y^{6-4a}
This simplifies the numerator to a single power of yy.
3
Apply the quotient rule of exponents, xmxn=xmn\frac{x^m}{x^n} = x^{m-n}, to divide by the denominator.
y64ay5=y(64a)5=y14a\frac{y^{6-4a}}{y^5} = y^{(6-4a) - 5} = y^{1-4a}
This simplifies the entire rational expression into a single exponential expression.
4
Equate the simplified exponent to the exponent of the equivalent expression and solve the linear equation for aa.
14a=7    4a=8    a=21-4a = -7 \implies -4a = -8 \implies a = 2
Since the bases are equal and non-zero, their exponents must be equal for the expressions to be equivalent.

Anahtar Kavram

Properties of Exponents in Algebraic Expressions
Tahmini Süre:1m 30s
Soru 1997Soru

If the quadratic expression 6x27x56x^2 - 7x - 5 is factored completely into the product of two linear binomials of the form (ax+b)(cx+d)(ax + b)(cx + d), where aa, bb, cc, and dd are integers such that a>c>0a > c > 0, what is the value of the expression adbcad - bc?

Cevabı ve açıklamayı göster

Cevap: 13

Cevap

The value of the expression adbcad - bc is 13.

Adım Adım Çözüm

1
Factor the quadratic expression 6x27x56x^2 - 7x - 5.
(3x5)(2x+1)(3x - 5)(2x + 1)
Find two numbers that multiply to 6×(5)=306 \times (-5) = -30 and add to 7-7, which are 10-10 and 33. Rewrite the middle term and factor by grouping: 6x210x+3x5=2x(3x5)+1(3x5)=(3x5)(2x+1)6x^2 - 10x + 3x - 5 = 2x(3x - 5) + 1(3x - 5) = (3x - 5)(2x + 1).
2
Determine the values of the coefficients aa, bb, cc, and dd.
a=3a = 3, b=5b = -5, c=2c = 2, and d=1d = 1
The expression is factored into the form (ax+b)(cx+d)(ax + b)(cx + d) where a>c>0a > c > 0. Comparing the factors (3x5)(3x - 5) and (2x+1)(2x + 1), we see the coefficients of xx are 33 and 22. Since 3>2>03 > 2 > 0, we have a=3a = 3 and c=2c = 2. This leaves b=5b = -5 and d=1d = 1.
3
Calculate the value of adbcad - bc.
13
Substitute a=3a = 3, b=5b = -5, c=2c = 2, and d=1d = 1 into the expression: adbc=(3)(1)(5)(2)=3+10=13ad - bc = (3)(1) - (-5)(2) = 3 + 10 = 13.

Anahtar Kavram

Factoring quadratic polynomials of the form ax2+bx+cax^2 + bx + c with a>1a > 1.
Soru 1998Soru

A system of equations is given below:

y=(x1)26y=x1\begin{aligned} y &= (x - 1)^2 - 6 \\ y &= x - 1 \end{aligned}

If (x,y)(x, y) is a solution to this system in the first quadrant, what is the value of x+yx + y?

Cevabı ve açıklamayı göster

Cevap: 7

Cevap

The sum of the coordinates of the first quadrant solution is 7.
To solve the system, substitute the expression for yy from the linear equation into the quadratic equation to get x1=(x1)26x - 1 = (x - 1)^2 - 6. Substituting u=x1u = x - 1 yields u2u6=0u^2 - u - 6 = 0. Factoring the quadratic expression gives (u3)(u+2)=0(u - 3)(u + 2) = 0, so u=3u = 3 or u=2u = -2. Since u=x1u = x - 1, this means x=4x = 4 or x=1x = -1. Evaluating both cases gives the intersection points (4,3)(4, 3) and (1,2)(-1, -2). Only (4,3)(4, 3) is in the first quadrant. Adding these coordinates together yields 4+3=74 + 3 = 7.

Adım Adım Çözüm

1
Substitute y=x1y = x - 1 into the quadratic equation to set up an equation in terms of xx.
x1=(x1)26x - 1 = (x - 1)^2 - 6
To find the xx-coordinates of the intersection points.
2
Solve the equation for xx by substituting u=x1u = x - 1.
u=u26u2u6=0(u3)(u+2)=0u = u^2 - 6 \Rightarrow u^2 - u - 6 = 0 \Rightarrow (u - 3)(u + 2) = 0. This gives u=3u = 3 or u=2u = -2.
To find the values of the substituted variable uu.
3
Find the corresponding xx and yy values for both cases.
Case 1: x1=3x=4x - 1 = 3 \Rightarrow x = 4, which gives y=3y = 3. Point is (4,3)(4, 3). Case 2: x1=2x=1x - 1 = -2 \Rightarrow x = -1, which gives y=2y = -2. Point is (1,2)(-1, -2).
To determine the full coordinates of all intersection points.
4
Identify the first quadrant solution and calculate the sum of its coordinates.
The first quadrant solution is (4,3)(4, 3). The sum of the coordinates is 4+3=74 + 3 = 7.
To answer the question's requirement for the sum of coordinates in the first quadrant.

Anahtar Kavram

Solving systems of linear and quadratic equations by substitution and identifying quadrant-specific solutions.
Soru 1999Soru

The equation of a circle is x2+y2=25x^2 + y^2 = 25, and the equation of a line is 2xy=52x - y = 5. If the line intersects the circle at the points PP and QQ, what is the sum of the yy-coordinates of PP and QQ?

Cevabı ve açıklamayı göster

Cevap: -2

Cevap

The sum of the yy-coordinates is 2-2.
Substituting the linear equation into the circle equation yields a quadratic equation with roots x=0x = 0 and x=4x = 4. Evaluating the linear equation at these values gives the yy-coordinates 5-5 and 33. Adding these yy-coordinates results in 2-2.

Adım Adım Çözüm

1
Rearrange the linear equation to express yy in terms of xx.
y=2x5y = 2x - 5
Expressing one variable in terms of the other allows for substitution into the quadratic circle equation.
2
Substitute y=2x5y = 2x - 5 into the circle equation x2+y2=25x^2 + y^2 = 25 and simplify.
x2+(2x5)2=25    x2+4x220x+25=25    5x220x=0x^2 + (2x - 5)^2 = 25 \implies x^2 + 4x^2 - 20x + 25 = 25 \implies 5x^2 - 20x = 0
This substitution reduces the system of equations to a single quadratic equation in terms of xx.
3
Solve the quadratic equation 5x220x=05x^2 - 20x = 0 for xx.
5x(x4)=0    x1=05x(x - 4) = 0 \implies x_1 = 0 and x2=4x_2 = 4
Finding the roots of this quadratic equation gives the xx-coordinates of the intersection points.
4
Substitute the xx-values back into the linear equation y=2x5y = 2x - 5 to find the corresponding yy-coordinates.
For x1=0x_1 = 0, y1=2(0)5=5y_1 = 2(0) - 5 = -5. For x2=4x_2 = 4, y2=2(4)5=3y_2 = 2(4) - 5 = 3. The intersection points are P(0,5)P(0, -5) and Q(4,3)Q(4, 3).
This step determines the coordinates of the two points of intersection.
5
Calculate the sum of the yy-coordinates of the points PP and QQ.
y1+y2=5+3=2y_1 + y_2 = -5 + 3 = -2
This yields the final value requested by the question.

Anahtar Kavram

Solving a system of linear and circular equations by substitution
Tahmini Süre:2m 0s
Soru 2000Soru

What is the value of the larger real solution to the equation 10x3x1=2\frac{10}{x} - \frac{3}{x-1} = 2?

Cevabı ve açıklamayı göster

Cevap: 2.5

Cevap

The larger real solution is 2.52.5.
Multiplying the equation by the least common denominator x(x1)x(x-1) yields 10(x1)3x=2x(x1)10(x-1) - 3x = 2x(x-1). Simplifying this leads to 2x29x+10=02x^2 - 9x + 10 = 0. Factoring the quadratic yields (2x5)(x2)=0(2x-5)(x-2) = 0, which gives the solutions x=2.5x = 2.5 and x=2x = 2. The larger of these two solutions is 2.52.5.

Adım Adım Çözüm

1
Multiply the entire equation by the least common denominator, which is x(x1)x(x-1), for x0x \neq 0 and x1x \neq 1.
10(x1)3x=2x(x1)10(x-1) - 3x = 2x(x-1)
This clears the fractions from the rational equation.
2
Expand both sides of the equation.
10x103x=2x22x10x - 10 - 3x = 2x^2 - 2x
Expanding the terms allows us to combine like terms.
3
Combine like terms on the left side and move all terms to one side to set the quadratic equation equal to zero.
2x29x+10=02x^2 - 9x + 10 = 0
Setting the quadratic equation to zero is required to solve it by factoring.
4
Factor the quadratic equation by grouping.
(2x5)(x2)=0(2x-5)(x-2) = 0
Factoring allows us to find the roots of the quadratic equation.
5
Solve for xx by setting each factor equal to zero.
x=2.5x = 2.5 or x=2x = 2
By the zero product property, at least one of the factors must be zero.
6
Check for extraneous solutions and select the larger real value.
Both 22 and 2.52.5 are valid because they do not make the original denominators zero. The larger value is 2.52.5.
The question specifically asks for the larger of the two real solutions.

Anahtar Kavram

Solving rational equations by clearing denominators
Tahmini Süre:1m 30s
ÖncekiSayfa 100 / 278Sonraki
Tüm alıştırma soruları — ACT | Examkin