(A,B) =
1 0 1 2 1 2
-1 2 0 -3 1 1
0 4 1 1 0 1
r2+r1
1 0 1 2 1 2
0 2 1 -1 2 3
0 4 1 1 0 1
r3-2r2
1 0 1 2 1 2
0 2 1 -1 2 3
0 0 -1 3 -4 -5
r1+r3,r2+r3
1 0 0 5 -3 -3
0 2 0 2 -2 -2
0 0 -1 3 -4 -5
r3*(-1),r2*(1/2)
1 0 0 5 -3 -3
0 1 0 1 -1 -1
0 0 1 -3 4 5
所以 X =
5 -3 -3
1 -1 -1
-3 4 5