Question

Question 7(Multiple Choice Worth 5 points)
(04.07A LC)
Which equation does the graph below represent?
15
12
9
6
3
2 3 4 5
-5 -4 -3 -2 -1 01
31
-6
.9
-12
-15
y =
y = -3x
y = 3x
y = x

Answer 1

Answer:

$y = -3x$

Step-by-step explanation:

Given

The attached graph

Required

Determine the graph equation

To do this, we pick any 3 corresponding points of x and y

$(x_1,y_1) = (0,0)$

$(x_2,y_2) = (2,-6)$

$(x_3,y_3) = (-4,12)$

The equation can then be solved using linear interpolation as follows:

$\frac{y-y_3}{x-x_3} = \frac{y_2 - y_1}{x_2-x_1}$

This gives:

$\frac{y-12}{x-(-4)} = \frac{-6 -0}{2-0}$

$\frac{y-12}{x+4} = \frac{-6 -0}{2-0}$

$\frac{y-12}{x+4} = \frac{-6}{2}$

$\frac{y-12}{x+4} = -3$

Multiply both sides by x + 4

$(x + 4) * \frac{y-12}{x+4} = -3 * (x + 4)$

$y - 12 = -3 *(x + 4)$

Open bracket

$y - 12 = -3x -12$

Add 12 to both sides

$y - 12+12 = -3x -12+12$

$y = -3x$