Question 5

Prove that the points whose position vectors are $A(-6\mathbf{i} + 3\mathbf{j} + 2\mathbf{k})$, $B(3\mathbf{i} - 2\mathbf{j} + 4\mathbf{k})$, $C(5\mathbf{i} + 7\mathbf{j} + 3\mathbf{k})$, $D(-13\mathbf{i} + 17\mathbf{j} - \mathbf{k})$ are coplanar.