You add 8 and 5 so the equation would be 8+5=13
I know this is not an answer but if your having trouble with this there is a website called Desmos all you do is type in the equation for the graph and it gives you the answer
Answer:
Step-by-step explanation:
(-7, 8) (-8, 8)
(y2 - y1) / (x2 - x1)
(8 - 8) / (-8 + 7)
0 / -1
the slope is 0
you could also see this because the y value doesn't change
if the y value doesn't change the slope is 0, if the x value doesn't change the slope is undefined