put y=0 & find x. call it x1.
put x=0 & find y. call it y1.
define the points (x1, 0) & (0, y1) on a cartesian plane. connect the points with a line to find the interception.
You will see a tiny picture up top of the question and draw it out and added then work
Gradient
= (y2-y1)/(x2-x1)
= (-9-(-5))(-2-(-4))
= (-4)(2)
= -8
This is the associative property of addition
