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Zorluk: ZorSystems of Linear Equations

The table below shows several values of xx and the corresponding values of two linear functions, ff and gg.

xxf(x)f(x)g(x)g(x)
2-212123-3
006611
220055
446-699

If the system of equations y=f(x)y = f(x) and y=g(x)y = g(x) has solution (x,y)(x, y), what is the value of x+yx + y?

  1. A
    20-20
  2. 44Cevap
  3. C
    1010
  4. D
    167\frac{16}{7}

Cevap

The sum of the coordinates of the solution to the system is 44.
To find the solution to the system y=f(x)y = f(x) and y=g(x)y = g(x), we must first determine the equations of the linear functions ff and gg from the given table. For f(x)f(x), using the points (0,6)(0, 6) and (2,0)(2, 0), the slope is 0620=3\frac{0 - 6}{2 - 0} = -3. Since the yy-intercept is 66, the equation is f(x)=3x+6f(x) = -3x + 6. For g(x)g(x), using the points (0,1)(0, 1) and (2,5)(2, 5), the slope is 5120=2\frac{5 - 1}{2 - 0} = 2. Since the yy-intercept is 11, the equation is g(x)=2x+1g(x) = 2x + 1. Setting the two equations equal to find their intersection gives 3x+6=2x+1-3x + 6 = 2x + 1. Solving for xx yields 5x=55x = 5, or x=1x = 1. Substituting x=1x = 1 into g(x)g(x) gives y=2(1)+1=3y = 2(1) + 1 = 3. The sum of the coordinates of the solution is x+y=1+3=4x + y = 1 + 3 = 4.

Adım Adım Çözüm

1
Determine the linear equation for f(x)f(x) using the table values.
f(x)=3x+6f(x) = -3x + 6
The slope of ff is calculated as f(2)f(0)20=062=3\frac{f(2) - f(0)}{2 - 0} = \frac{0 - 6}{2} = -3. Since f(0)=6f(0) = 6, the yy-intercept is 66.
2
Determine the linear equation for g(x)g(x) using the table values.
g(x)=2x+1g(x) = 2x + 1
The slope of gg is calculated as g(2)g(0)20=512=2\frac{g(2) - g(0)}{2 - 0} = \frac{5 - 1}{2} = 2. Since g(0)=1g(0) = 1, the yy-intercept is 11.
3
Set f(x)=g(x)f(x) = g(x) to solve for the xx-coordinate of the intersection.
x=1x = 1
Equating the two expressions gives 3x+6=2x+1-3x + 6 = 2x + 1. Adding 3x3x to both sides and subtracting 11 from both sides results in 5x=55x = 5, which simplifies to x=1x = 1.
4
Substitute x=1x = 1 back into either equation to solve for yy.
y=3y = 3
Using the equation g(x)=2x+1g(x) = 2x + 1, substituting x=1x = 1 gives y=2(1)+1=3y = 2(1) + 1 = 3.
5
Calculate the sum x+yx + y.
44
Adding the coordinates of the solution (1,3)(1, 3) gives 1+3=41 + 3 = 4.

Anahtar Kavram

Solving a system of linear equations derived from a table of values.
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