r2+2r1,r3-r1,r4+r1
1 2 3 2
0 5 4 -1
0 -3 -4 -1
0 4 4 0
r4*(1/4),r1-2r4,r2-5r4,r3+3r4
1 0 1 2
0 0 -1 -1
0 0 -1 -1
0 1 1 0
r1+r2,r3-r2,r4+r2,r2*(-1)
1 0 0 1
0 0 1 1
0 0 0 0
0 1 0 -1
交换行
1 0 0 1
0 1 0 -1
0 0 1 10 0 0 0