A=
3/2 0 0
0 4/3 0
0 0 6/5
因为 AB-2A=B
所以 (A-E)B = 2A
所以 B=2(A-E)^-1A
A-E=
1/2 0 0
0 1/3 0
0 0 1/5
(A-E)^-1=
2 0 0
0 3 0
0 0 5
所以 B = 2*
3 0 0
0 4 0
0 0 6
=
6 0 0
0 8 0
0 0 12