3 1 -1 2
-5 1 3 -4
2 0 1 -1
1 -5 3 -3
D = -1
1 -5 3 -3
-5 1 3 -4
2 0 1 -1
3 1 -1 2
D = -1
1 -5 3 -3
0 -24 18 -19
0 10 -5 5
0 16 -10 11
D = -1
-24 18 -19
10 -5 5
16 -10 11
D =
10 -5 5
-24 18 -19
16 -10 11
D = 5
2 -1 1
-24 18 -19
16 -10 11
D = 5
2 -1 1
0 6 -7
0 -2 3
= 5*2*(6*3-2*7)
= 40