第 1 列的 - 1 倍加到第2,3,4列,A 初等行变换为
[1 1 1 1]
[0 0 -2 -2]
[0 -2 0 -2]
[0 -2 -2 0]
A 初等行变换为
[1 1 1 1]
[0 0 1 1]
[0 1 0 1]
[0 1 1 0]
A 初等行变换为
[1 0 1 0]
[0 1 0 1]
[0 0 1 -1]
[0 0 1 1]
A 初等行变换为
[1 0 1 0]
[0 1 0 1]
[0 0 1 -1]
[0 0 0 2]
A 初等行变换为
[1 0 0 0]
[0 1 0 0]
[0 0 1 0]
[0 0 0 1]
其实书上都有介绍