┏1 1 1 | 1 0 0┓┃0 1 -1 | 0 1 0 ┃┗1 -1 1 | 0 0 1 ┛ →﹙行初等变换﹚→┏1 0 0 | 0 1 1 ┓┃0 1 0 | 1/2 0 -1/2┃┗0 0 1 | 1/2 -1 -1/2┛ 所求逆矩阵为┏ 0 1 1 ┓┃1/2 0 -1/2┃┗ 1/2 -1 -1/2