Points are ( 0,-5) (5, -3)

Question

what is the value of x when y is -7

Answer 1

Are supposed to assume that these two points determine the graph (i.e. a straight line)>

 

If so, we have been given that y-intercept is -5, and the slope is -3 - (-5)/(5-0) = 2/5.

 

therefore y = (2/5)x -5.  If y = -7, -7 = (2/5)x - 5

-2 = (2/5)x

x = (5/2)(-2) = -5.

Answer 2

Firstly, find the equation of the straight line:

 

(y-y₁)/(y_1-y2)=(x-x₁)/(x₁-x₂)

=> 5y-2x+25=0

 

Find x for given y:

 

5*(-7)-2x+25=0

=>x=-5