3:29 .. .I .... 96 11. The points A(1, 0, 2), B(2, 0, 1), and C(1, 2, k) form a triangle of area V6. Determine the value(s) ofk. [5] 12. Given the vectors u = (-1,1,1) , v = (2,1, -3) , and W = (5,1, -7) , calculate the value of each of the following: a) ux v[2] b) v x w[2] c) u. (v x w) [2] d) (ux v) x (v x w) [2] Thinking 13. If la| = 12 , b| = 17 Find: a 40 a) Proj (a on b) [2] b) Proj (b on a) [2] c) (2a - b) . (a + 3b) [4]