Question

The matrix M = `[(0,1,2),(1,2,3),(3,1,1)]` and its inverse is N = [nij]. What is the element n₂₃ of matrix N?

Options

• 2

• -2

• 1

• -1

Answer 1

-1

Explanation:

Since, N = M^-1

∴ N = `"adj M"/|"M"| = ([(∗,∗,∗),(∗,∗,2),(∗,∗,∗)])/-2`

`= [(∗,∗,∗),(∗,∗,-1),(∗,∗,∗)]`

∴ n₂₃ = - 1