D=|1 -2 3 2|
0 -1 -2 -3 r2-r1*2、r3+r1*3、r4-r1*1
0 -10 3 7
0 4 -4 1
=|1 -2 3 2|
0 -1 -2 -3
0 0 23 37 r3-r2*10、r4+r2*4
0 0-12-11
=|1 -2 3 2|
0 -1 -2 -3
0 0 -1 15 r3+r4*2
0 0 -12 -11
=|1 -2 3 2|
0 -1 -2 -3
0 0 -1 15
0 0 0 -191 r4-r3*12
=1*(-1)*(-1)*(-191) =-191
建议你学会用excel一步步验算.