1 -1 3 -4 3
3 -3 5 -4 1
2 -2 3 -2 0
3 -3 4 -2 -1
r4-r2,r2-r1-r3,r3-2r1
1 -1 3 -4 3
0 0 -1 2 -2
0 0 -3 6 -6
0 0 -1 2 -2
r2*(-1),r1-3r2,r3+3r2,r4+r2
1 -1 0 2 -3
0 0 1 -2 2
0 0 0 0 0
0 0 0 0 0