8. Consider the vectors u = (2, -1, 1) and u = (1, 1, 2). Determine the angle 0 between u and v. (3 marks) 9. Show that the vector a = (5, 9, 14) can be written as a linear combination of the vectors b and d, where b = (-2, 3, 1) and c = (3, 1, 4). (4 marks