Answer:
Since the Line is Perpendicular
m.m'=-1
The line
y=x+8
Comparing with
Y=mx + C
m=1
m.m'=-1
m'=-1/m = -1/1 = -1.
y-y' = m'(x-x')
The point it passes is (-7,8)
y-8= -1(x--7)
y-8=-1(x+7)
y-8 = -x - 7
y + x -1 = 0.
or In Slope intercept Form
Just Make y the subject
y= -x + 1 ..... This is your answer.
Hope this helps!!!