行列式
1 2 -1 3
2 -1 3 -2
0 3 -1 1
1 -1 1 4
r2-2r1,r4-r1
1 2 -1 3
0 -5 5 -8
0 3 -1 1
0 -3 2 1
r3+r4,r4-(3/5)r2
1 2 -1 3
0 -5 5 -8
0 0 1 2
0 0 -1 29/5
r4+r3
1 2 -1 3
0 -5 5 -8
0 0 1 2
0 0 0 39/5
故行列式 = -39.
2 2 -1 3
7 -1 3 -2
6 3 -1 1
-4 -1 1 4
c1-3c2-2c3+c4 此行列式化为第一个行列式,故行列式=-39.