Question

线性代数计算题计算：

计算： ．4 1 -1
2 -1 2
2 1 -1
这一堆数两边是大竖线，求解

Answer 1

解: D =
r1-2r3,r2-r3
0 -1 1
0 -2 3
2 1 -1

r2-2r1
0 -1 1
0 0 1
2 1 -1

交换行(2次)
2 1 -1
0 -1 1
0 0 1

D = -2.

Answer 2

4 1 -1 2 0 0
2 -1 2 = 2 -1 2= 2*| -1 2| =2*(1-2)=-2
2 1 -1 2 1 -1 1 -1