2 1 -3 2
3 2 1 -2
1 1 4 -4
=====
1 1 4 -4
0 -1 -11 10
0 -1 -11 10
=====
1 1 4 -4
0 1 11 -10
0 0 0 0
==========
1 0 -7 6
0 1 11 -10
0 0 0 0
x1=7x3-6x4
x2=-11x3+10x4
取x3=1,x4=0,得
x1=7,x2=-11
ξ1=(7,-11,1,0)T
取x3=0,x4=1,得
x1=-6,x2=10
ξ2=(-6,10,0,1)T
所以
ξ1=(7,-11,1,0)T,ξ2=(-6,10,0,1)T为一个基础解系
通解为x=c1ξ1+c2ξ2.