Answer:
-
and

Explanation:
Calculate the slope m using the slope formula
m =

with (x₁, y₁ ) = (- 8, 8) and (x₂, y₂ ) = (4, - 8) ← 2 points on green line
m =
=
= -

Repeat with (x₁, y₁ ) = (0, - 1) and (x₂, y₂ ) = (4, 2) ← 2 points on the blue line
m =
=

Since the product of the slopes = -
×
= - 1
Then the lines are perpendicular