(A,E)=
1 2 0 1 0 0
2 1 -1 0 1 0
3 1 1 0 0 1
r2-2r1,r3-3r1
1 2 0 1 0 0
0 -3 -1 -2 1 0
0 -5 1 -3 0 1
r3-2r2
1 2 0 1 0 0
0 -3 -1 -2 1 0
0 1 3 1 -2 1
r1-2r3,r2+3r3
1 0 -6 -1 4 -2
0 0 8 1 -5 3
0 1 3 1 -2 1
r2*(1/8),r2r3
1 0 -6 -1 4 -2
0 1 3 1 -2 1
0 0 1 1/8 -5/8 3/8
r1+6r3,r2-3r3
1 0 0 -1/4 1/4 1/4
0 1 0 5/8 -1/8 -1/81
0 0 1 1/8 -5/8 3/8
逆矩阵就是右边那个3*3的