123解：1）221:=2.·343再由.A可逆.Ai =2, Ai = 6, Ai =-4,Az = -3, A22 = -6, A32 = 5,A13 = 2, A23 = 2, A3 = -2.6-4A有 A-153-62A22284.4矩阵的逆§4.4 矩阵的逆 解：1） 1 2 3 2 2 1 2, 3 4 3 = ∴ A可逆. 12 22 32 A A A = − = − = 3, 6, 5, 11 21 31 A A A = = = − 2, 6, 4, 13 23 33 A A A = = = − 2, 2, 2. 再由 * 1 2 6 4 1 3 6 5 . 2 222 A A A −   − = = − −       有