Hi MHF,

I'm having heaps of trouble working out how to solve this question. The text book that I am using is the third addition of Lay's Linear Algebra book and I cant find any examples on this type of question..

Suppose A is a square matrix which satisfies the matrix equation

$\displaystyle A^4+5A^2-5I=0$

Determine whether A is invertible or not. If it is invertible, then provide an expression for the inverse of A.