ASAP! anyone know the answer to this and possible show me how to solve it.

Answer:
n = - 3
Step-by-step explanation:
Slope line r: (5-1)/(3+1) = 4/4 = 1
Slope of the perpendicular line: -1
p=(-4,4)
y-intercept: 4 - (-1)(-4) = 4 - 4 = 0
y = -x
(3,n) x = 3 and y = n
n = - 3