A =
1 1 -1 -1
2 -5 5 2
7 -7 5 1
-->
1 1 -1 -1
0 -7 7 4
0 -14 12 8
-->
1 1 -1 -1
0 -7 7 4
0 0 -2 0
-->
1 1 0 -1
0 -7 0 4
0 0 1 0
-->
1 0 0 -3/7
0 1 0 -4/7
0 0 1 0
通解为 c(3,4,0,7)^T
A =
1 1 -1 -1
2 -5 5 2
7 -7 5 1
-->
1 1 -1 -1
0 -7 7 4
0 -14 12 8
-->
1 1 -1 -1
0 -7 7 4
0 0 -2 0
-->
1 1 0 -1
0 -7 0 4
0 0 1 0
-->
1 0 0 -3/7
0 1 0 -4/7
0 0 1 0
通解为 c(3,4,0,7)^T