The coordinates of the vertices of a quadrilateral are A(-2, 5), B(6, 5), C(4, -3), and D(-4, -3). Use slope to show that ABCD is a parallelogram.

Answer 1

show that slope AB = slope DC
and slope AD = slope BC

I will do the first pair, you do the second

slope AB = (5-5)/6+2) = 0/8 = 0
slope DC = (-3+3)/(-4-4) = 0/-8 = 0
so AB || DC

test if AD || BC
if so, then by definition, it is a parallogram.