23 3-4 0-3-4 4≠0,所以A可逆 11 同理可求得 2 3 2 = A23=-1,A3=-3 1616 0 1 0 0 3 4 1 2 3 = − − 1 0 − 3 − 4 = = 4 0, 所以A可逆. 3, 3 3 1 2  A11 = = − 4, 1 3 2 2 A12 = − = − 5, 1 3 2 1 A13 = = 21 31 22 32 23 33 3, 1, 0, 4, 1, 3. A A A A A A = = = = = − = − 同理可求得