解下列矩阵方程：
(1)
(12
33)
X=
(12
21)
(2)X
(11-2
022
1-10)
=
(1-43
20-1
1-20)
(1)所以 A11=3，A12=-3，A21=-2，A22=1 又|A|=-3 所以 A-1=(1/|A|)=-(1/3) (3 -2 -3 1) = (-1 2/3 1 -(1/3)) 所以 X= (-1 2/3 1 -(1/3)) (1 2 2 1) = (1/3 -(4/5) 1/3 5/3) (2)所以 A= (1 1 -2 0 2 2 1 -1 0) =8≠0，所以 A可逆 又A11=2，A12=2,A13=-2，A21=2，A22=2，A23=2，A31= 6，A32=-2，A33=2 所以 A-1=(1/|A|)A*=1/8 (2 2 6 2 2 -2 -2 2 2) = (1/4 1/4 3/4 1/4 1/4 -(1/4) -(1/4) 1/4 1/4) 所以 X= (1 -4 3 2 0 -1 1 -2 0) (1/4 1/4 3/4 1/4 1/4 -(1/4) -(1/4) 1/4 1/4) = -(2/3 0 5/2 3/4 1/4 5/4 -(1/4) -1/4 5/4)
