Question

线性代数题，求19题的第2小题，要详细解答过程，最好发图片清楚一点，我想问一下这有什么技巧

Answer 1

[A|E] =
2 0 1 1 0 0

1 -2 -1 0 1 0
-1 3 2 0 0 1

[A|E] =
1 -2 -1 0 1 0
2 0 1 1 0 0
-1 3 2 0 0 1

[A|E] =
1 -2 -1 0 1 0
2 0 1 1 0 0
-1 3 2 0 0 1

[A|E] =
1 -2 -1 0 1 0
0 4 3 1 -2 0
0 1 1 0 1 1
ans =
1 -2 -1 0 1 0
0 1 1 0 1 1
0 4 3 1 -2 0
ans =
1 -2 -1 0 1 0
0 1 1 0 1 1
0 4 3 1 -2 0

[A|E] =
1 -2 -1 0 1 0
0 1 1 0 1 1
0 0 -1 1 -6 -4

[A|E] =
1 -2 -1 0 1 0
0 1 1 0 1 1
0 0 1 -1 6 4

[A|E] =
1 -2 0 -1 7 4
0 1 0 1 -5 -3
0 0 1 -1 6 4

[A|E] =
1 0 0 1 -3 -2
0 1 0 1 -5 -3
0 0 1 -1 6 4

A^(-1) =
1 -3 -2
1 -5 -3
-1 6 4