- #1

- 595

- 0

## Homework Statement

Let A = [3 2 1; 0 1 4; 4 2 1]

(i) Find the cofactors C11, C12, C13, C21, C22, C23, C31, C32, C33 of A.

(ii) Given that det(A) = 7, use the adjoint method to find A-1.

(iii) Use the answer to part (ii) to find A-1 over the prime field Z5.

## The Attempt at a Solution

For (i) and (ii) I got inverse of A = 1/7[-7 0 7; 16 -1 -12; -4 2 3]

no problems here,

Just wondering how I do part (iii)

I've had a peek at the solutions and relevant textbooks, but can't seem to find anything.

Thanks