Question

Is the line through points P(2,-9) and Q(6, -13) perpendicular to the line through points R(5,-1) and

Answer 1

Line through P(0, 5) and Q(-1, 8):
slope = m = (y2 - y1) / (x2 - x1) = (8 - 5) / (-1 - 0) = 3 / -1 = -3

line through R(3, 3) and S(5, -1):
slope = m = (y2 - y1) / (x2 - x1) = (-1 - 3) / (5 - 3) = -4 / 2 = -2

Parallel lines have equal slopes. Since the two lines have different slopes, they are not parallel.