解 321 A=111|,|A=0 2≠0 01 00 A=02-2,A 02 121 12 2021/2/202021/2/20 12 解 * 1 3 2 1 2 2 1 1 1 1 , | | 0 1 1 2 0 1 0 1 0 0 1 1 2 1 1 2 1 1 0 2 2 , 0 2 2 2 1 2 1 1 2 1 A A A A-     = = =            - -     = - = -     - -