(a) Show that if a square matrix A is invertible, then A" is invertible for each n N and its inverse is given by (A") = (A)". (Note that A" means the matrix A multiply by itself n times). (b) (5 marks) Find the inverse of the matrix A = [1 4-5 1 2, if it exists. [1 a (c) (3 marks) Find all values of a, b and c in R for which the matrix A = is I 00 invertible