### Invertible Matrix over Complex Numbers

Let A be a square n x n matrix over C[X] and write A = [pjk (X)] . For any z∈C( z being a complex variable) let A(z) := [pj k (z)] , that is a square n x n matrix over C. Show that matrix A is invertible if and only if matrix A(z) is invertible for all z from C. Will it be still valid if we change complex numbers into