r3+r1
11-22
02-13
01 -13
r1-r3,r2-2r3
1 0 -1 -1
0 01 -3
0 1 -1 3
r1+r2,r3+r2
1 00 -4
0 01 -3
0 100
r2r3
1 0 0 -4
0 1 00
0 0 1 -3