The points (−3, 1), (−6, −7), (3, −9), (6, −1) are
Vertices of a rectangle
Collinear
Vertices of a parallelogram
Vertices of a rhombus
A(−3,1),B(−6,−7),C(3,−9),D(6,−1)
A+C=B+D
AB↔ slope =−83
BC↔ slope =−29
AB¯=9+64=73,BC=81+4=85
AB≠BC⇒ A,B,C,D forms a parallelogram