Question

四阶行列式问题,先放50,有追分,

Answer 1

2-2r1,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

= -39.