Hello, I need the answer to this question please.

2. (20 pts) Note that parts (a) and (b) are not related. (a) Suppose that A is an invertible n x n matrix that satisfies A + A - I. Show that A = I + A and that A3 - -/ + 2A. (12 pts) (b) Suppose that A and B are invertible n x n matrices and that A'A = In. Calculate (A'B A)(A'BA). What is the inverse of (A'BA)? (8 pts)