Please do a, b, c

C1 2. In this question, we prove that the area of the triangle 71 equals , det 2 yz [8 marks] (13, y3) B 71 (I2, y2) I1, yl) 12 A O (a) Let 72 be the triangle obtained from 71 by translating the plane from (71, y1) to (0, 0). Find the coordi- nates of A and B. (b) Show that 72 has area , det ($2 -X1) (23 - 21) (12 - 41) (23 - 21) (c) Show that yl 0 det T2 det x1 (12 - 21) (23 - 71) = det (12 - 21) (13 - 11) yl (72 - y1) (23 - 31 ) (32 - 31) (43 - 31) y3