1 -2 3 -1 1
3 -1 5 -3 2
2 1 2 -2 3
r2-r1-r3,r3-2r1
1 -2 3 -1 1
0 0 0 0 -2
0 5 -4 0 1
r2*(-1/2),r1-r2,r3-r2
1 -2 3 -1 0
0 0 0 0 1
0 5 -4 0 0
r3*(1/5),r1+2r3
1 0 7/5 -1 0
0 1 -4/5 0 0
0 0 0 0 1