(vii) If P is a invertible square matrix, then
(viii) P = diag(a1, a2, a3......an)
⇒ P–1 = diag(a–11, a–12, a–13......a–1n).
(ix) Inverse of a diagonal matrix is also diagonal.
(x) Inverse of a triangular matrix is also triangular.
(xi) Inverse of a scalar matrix is also a scalar matrix.
(xii) Every invertible matrix possesses a unique inverse.