|-2 2 -4 0| r1-r3*2 |-8 0 0 6|
4 -1 3 5 = r2+r3 = 7 0 1 2
3 1 -2 -3 3 1 -2 -3
2 0 5 1 2 0 5 1
= r4-r2*5=|-8 0 0 6| =6*|-4 0 0 3|
7 0 1 2 7 0 1 2
3 1 -2 -3 3 1 -2 -3
-33 0 0 -9 -11 0 0 -3
=r1+r4=6*|-15 0 0 0|
7 0 1 2
3 1 -2 -3
-11 0 0 -3
=r4交换r3, =-6*|-15 0 0 0|
然后r3交换r2, -11 -3 0 0
然后c4交换c2 7 2 1 0
3 -3 -2 1
=-270