please explain it to me in details

2. (i) Let M be an invertible (m x m)-matrix, let N be an invertible (n x n)-matrix, let P be an (m x n)-matrix, and let Q be an (n x m)-matrix. Directly verify the Woodbury matrix identity (M + PNQ) -1 =M- -M-P(N-' +QM-'P)-1QM-1. (ii) Let A be an invertible (m x m)-matrix, let B be an (n x m)-matrix, let C be an (m x n)- matrix, and let D be an (n x n)-matrix. If the Schur complement S := D -BA C is invertible, then establish the blockwise inversion formula: A C A +A-ICS 'BA-1 -A 'CS-1] B D -S-BA-1 S-1