1-r2
1 -2 0 -2
5 6 0 7
0 2 11 7
7 0 9 6
c2+2c1,c4+2c1
1 0 0 0
5 16 0 17
0 2 11 7
7 14 9 20
=
16 0 17
2 11 7
14 9 20
r1-r2-r3,r3-7r2
0 -20 -10
2 11 7
0 -68 -29
= -2*
-20 -10
-68 -29
= -2*10*(29*2-68)
= 200.
帮忙计算线性代数的行列式, 详细步骤
1-r2
1 -2 0 -2
5 6 0 7
0 2 11 7
7 0 9 6
c2+2c1,c4+2c1
1 0 0 0
5 16 0 17
0 2 11 7
7 14 9 20
=
16 0 17
2 11 7
14 9 20
r1-r2-r3,r3-7r2
0 -20 -10
2 11 7
0 -68 -29
= -2*
-20 -10
-68 -29
= -2*10*(29*2-68)
= 200.