1-5r3
0 -3 -20 -34
0 -2 -1 0
1 0 4 7
0 3 0 2
r1+r4,r2+r4
0 0 -20 -32
0 1 -1 2
1 0 4 7
0 3 0 2
r4-3r2
0 0 -20 -32
0 1 -1 2
1 0 4 7
0 0 3 -4
r1+7r4
0 0 1 -60
0 1 -1 2
1 0 4 7
0 0 3 -4
r4-3r1
0 0 1 -60
0 1 -1 2
1 0 4 7
0 0 0 176
r1r4 ( 行列式变符号 )
1 0 4 7
0 1 -1 2
0 0 1 -60
0 0 0 176
行列式 = -176.