Answer:
m = (1 - 5)/(6 - (-4)) = -4/10 = -2/5
5 = (-2/5)(-4) + b
5 = 8/5 + b
b = 17/5
y = (-2/5)x + 17/5
Assume that line n is perpendicular to PQ. Line n will have slope 5/2.
The midpoint of PQ is ((-4 + 6)/2, (5 + 1)/2) = (1, 3).
3 = (5/2)(1) + b
3 = 5/2 + b
b = 1/2
y = (5/2)x + (1/2) could be the equation of line n.