The line parallel to k has the same slope as k: m = 2/5

We need the line that goes trough (20, -15) and has a slope m = 2/5. Now we can write:

y - (-15) = (2/5)(x - 20)

y + 15 = (2/5)x - 8

y = (2/5)x - 23

The line parallel to line k that passes through the point (20,-15) is y = (2/5)x - 23.

The line perpendicular to k has a slope equal to m = -(1/(2/5)) that is m = -5/2

Since the lone goes trough (20, -15) we have:

y - (-15) = (-5/2)(x - 20)

y + 15 = (-5/2)x + 50

y = (-5/2)x + 35

If we check the graph  of the lines we will see that indeed one is parallel and the other is perpendicular to k, and they both go trough (10, -15).