2-2r1,r3-2r3,r4-4r1
1 -2 2 1
0 0 -1 1
0 9 0 4
0 14 2 1
按第1列展开
D=
0 -1 1
9 0 4
14 2 1
c3+c2
0 -1 0
9 0 4
14 2 3
= 27 - 56
= -29
2-2r1,r3-2r3,r4-4r1
1 -2 2 1
0 0 -1 1
0 9 0 4
0 14 2 1
按第1列展开
D=
0 -1 1
9 0 4
14 2 1
c3+c2
0 -1 0
9 0 4
14 2 3
= 27 - 56
= -29