Question

Please Help! PreCalc Problem!

Let A = [2 9 1 5], B = [3 2 7 5] C = [5 -2 -7 3] a) Show that A is invertible and Find A^-1. b) Show that B and C are inverses. c) Solve the system using the Cramer's Rule: 2x + 9y = 12 x + 5y = 4 d) Compute A + B, A - B, -2A.