9. (5 marks) The vertices of quadrilateral ABCD are given as A(0, 3, 5), B(3, -1, 17), C(7, -3, 15), and D(4, 1, 3). Prove that ABCD is a parallelogram. Hint: Use the diagram given below, and use your knowledge in question #8 above and check if whether opposite sides (AB and DC) and (AD and BC) are form equal vectors. A B D