B=[1 2
2 5]
B的逆矩阵为[5 -2
-2 1]
BAB-1=[-1 0
0 2]
A=B-1[-1 0
0 2]B
A=[1 2 [-1 0 [5 -2 =[ -13 6
2 5] 0 2] -2 1] -30 14]