For the induction step use
I leave the details for you to fill in.
I'm having trouble starting because I haven't done induction in a long time. The problem says:
Let A be an n x n invertible matrix. Prove that for all m in the naturals, Am is invertible and determine a formula for its inverse in terms of A-1. Hint: use induction. My professor told us to only do this for m=2 and m=3.
Any help would be greatly appreciated!