①r2-2*r1,r3-2*r1得:1 2 2
0 -3 -6
0 -6 -3
②⅓r2,⅓r3得:1 2 2
0 -1 -2
0 -2 -1
③r3-2*r2得:1 2 2
0 -1 -2
0 0 3
④r2+r1得:1 2 2
0 1 0
0 0 3
⑤⅓r3,r1-2*r2得:1 0 2
0 1 0
0 0 1
⑥r1-2*r3得:1 0 0
0 1 0
0 0 1
即为所求的矩阵
①r2-2*r1,r3-2*r1得:1 2 2
0 -3 -6
0 -6 -3
②⅓r2,⅓r3得:1 2 2
0 -1 -2
0 -2 -1
③r3-2*r2得:1 2 2
0 -1 -2
0 0 3
④r2+r1得:1 2 2
0 1 0
0 0 3
⑤⅓r3,r1-2*r2得:1 0 2
0 1 0
0 0 1
⑥r1-2*r3得:1 0 0
0 1 0
0 0 1
即为所求的矩阵