X1+X2+X5=0
X1+X2-X3=0
X3+X4+X5=0
系数矩阵 =
1 1 0 0 1
1 1 -1 0 0
0 0 1 1 1
r2-r1
1 1 0 0 1
0 0 -1 0 -1
0 0 1 1 1
r3+r2,r2*(-1)
1 1 0 0 1
0 0 1 0 1
0 0 0 1 0
全部解为:c1(-1,1,0,0,0)' + c2(-1,0,-1,0,1)',其中c1,c2 为任意常数.
符号' 是转置.
2X1-4X2+5X3+3X4=0
3X1-6X2+4X3+2X4=0
4X1-8X2+17X3+11X4=0
系数矩阵 =
2 -4 5 3
3 -6 4 2
4 -8 17 11
--->
1 -2 0 -2/7
0 0 1 5/7
0 0 0 0
全部解为:c1(2,1,0,0)' + c2(2,0,-5,0,7)',其中c1,c2 为任意常数.