The question:

Long ago, a mathematician wrote and on a piece of paper. Unfortunately insects have damaged the paper and all that is left is:

a) Find

My attempt:

I tried finding the inverse of C the usual way, by substituting the asterixes with variables, and then setting up the following:

I tried reducing this to row echelon form, but it quickly became a mess, and I was unable to completely reduce it. Is my approach correct so far? Thanks.