1-r3,r2-3r3,r4-r3
3 0 4 15
-4 0 6 -24
3 -1 -1 17
1 0 4 2
按第2列展开,D=-1 *(-1)^(3+2) *
3 4 15
-4 6 -24
1 4 2
r1-3r3,r2+4r3
0 -8 9
0 22 -16
1 4 2
= -(8*16-9*22)
= -70.
1-r3,r2-3r3,r4-r3
3 0 4 15
-4 0 6 -24
3 -1 -1 17
1 0 4 2
按第2列展开,D=-1 *(-1)^(3+2) *
3 4 15
-4 6 -24
1 4 2
r1-3r3,r2+4r3
0 -8 9
0 22 -16
1 4 2
= -(8*16-9*22)
= -70.