帮我写一下线性代数!161页的20题的第3小题
1个回答

系数矩阵 A =

1 -2 1 1 -1

2 1 -2 -2 1

1 7 -5 -5 5

3 -1 -2 1 -1

r4-r1-r2,r3-r1,r2-2r1

1 -2 1 1 -1

0 5 -4 -4 3

0 9 -6 -6 6

0 0 -1 2 -1

r3-2r2

1 -2 1 1 -1

0 5 -4 -4 3

0 -1 2 2 0

0 0 -1 2 -1

r1-2r3,r2+5r3,r3*(-1)

1 0 -3 -3 -1

0 0 6 6 3

0 1 -2 -2 0

0 0 -1 2 -1

r1-r4,r2+6r4,r3-2r4

1 0 0 -9 2

0 0 0 18 -3

0 1 0 -6 2

0 0 -1 2 -1

r4*(-1),r2*(-1/3)

1 0 0 -9 2

0 0 0 -6 1

0 1 0 -6 2

0 0 1 -2 1

r1-2r2,r3-2r2,r4-r2

1 0 0 3 0

0 0 0 -6 1

0 1 0 6 0

0 0 1 4 0

交换行

1 0 0 3 0

0 1 0 6 0

0 0 1 4 0

0 0 0 -6 1

基础解系为 (3,6,4,-1,-6)^T.