confusing problem can you please help!!!! prove points?

Question

Prove that points A(5, 1), B(2, 4), C(-4, 2) and D(-1, -1) represent the vertices of a parallelogram. Show all your work and explain your solution.

Answer 1

vector AD = coordinates of D - coordinates of A = (-6, -2)
vector BC = (-6, -2): so AD and BC are parallel and of equal length
Also, vector AB = (3, -3) and vector DC = (3, -3), so AB and DC are parallel and of equal length.
So ADCB is a parallelogram.

Answer 2

put it in a graphing paper.