how did you get this

Question

If the slope is -4/5 it means 

(Δy/Δx) = -4/5 = (y-(-7))/(3-8) 

solving this algebraic equation yields y = -3.

Answer 1

Assuming the 2 given point are (3,y) and (8,-7),

 

m = -4/5 = [y - (-7)] / (3 - 8) = (y + 7) / (-5)

 

-4/5 = -(y + 7) / 5

 

4 = y + 7

 

y = -3

 

So what is your question?