依次做 r2+r1+r2,r1-r3-r4,r3-2r4
0 6 -5 6
0 2 3 -3
0 10 -5 5
1 -5 3 -3
r1-3r2,r3-5r2
0 0 -14 15
0 2 3 -3
0 0 -20 20
1 -5 3 -3
r1-(7/10)r3
0 0 0 1
0 2 3 -3
0 0 -20 20
1 -5 3 -3
r1r4
1 -5 3 -3
0 2 3 -3
0 0 20 -20
0 0 0 1
行列式 = 40.
依次做 r2+r1+r2,r1-r3-r4,r3-2r4
0 6 -5 6
0 2 3 -3
0 10 -5 5
1 -5 3 -3
r1-3r2,r3-5r2
0 0 -14 15
0 2 3 -3
0 0 -20 20
1 -5 3 -3
r1-(7/10)r3
0 0 0 1
0 2 3 -3
0 0 -20 20
1 -5 3 -3
r1r4
1 -5 3 -3
0 2 3 -3
0 0 20 -20
0 0 0 1
行列式 = 40.