解:
D=
2 1 1
1 1 1
1 2 1
=2+1+2-1-1-4=-1
D1=
4 1 1
3 1 1
4 2 1
=4+4+6-4-3-8=-1
D2=
2 4 1
1 3 1
1 4 1
=6+4+4-3-4-8=-1
D3=
2 1 4
1 1 3
1 2 4
=8+8+3-4-4-12=-1
所以x1=D1/D=1
x2=D2/D=1
x3=D3/D=1
2 1 1 4 1 1 2 4 1 2 1 4
1 1 1 =-1 3 1 1 =-1 1 3 1 =-1 1 1 3 =-1 故x1=1 x2=1 x3=1
1 2 1 4 2 1 1 4 1 1 2 4