Question

四阶行列式的计算,求简单方法.1 -3 0 -62 1 -5 10 2 -1 20 7 -7 12

Answer 1

2-2r1

1 -3 0 -6

0 7 -5 13

0 2 -1 2

0 7 -7 12

按第1列展开 D=

7 -5 13

2 -1 2

7 -7 12

c1+2c2,c3+2c2

-3 -5 3

0 -1 0

-7 -7 -2

按第2行展开 D = -1*

-3 3

-7 -2

= -(6+21) = -27