X(-7,5), Y(-1,-1)
first find the slope M
M = (xX - xY) / (yX - yY)
M = (5 - (-1))/(-7 -(-1)) = 6/-6 = -1 of the original line
Mp of the perpendicular line is 1.
midpoint of line is[(-7-(-1))/2 , (5 - (-1))/2]
(-3, 3)
slope form of the perpendicular is
y - 3 = x -(-3)
y = x +3 +3
y = x +6