是你算错了.计算如下:
(A,E) =
[ 1 0 0 0 1 0 0 0]
[ 0 1 0 0 0 1 0 0]
[-1 0 1 0 0 0 1 0]
[ 0 3 0 -6 0 0 0 1]
行初等变换为
[ 1 0 0 0 1 0 0 0]
[ 0 1 0 0 0 1 0 0]
[ 0 0 1 0 1 0 1 0]
[ 0 0 0 -6 0 -3 0 1]
行初等变换为
[ 1 0 0 0 1 0 0 0]
[ 0 1 0 0 0 1 0 0]
[ 0 0 1 0 1 0 1 0]
[ 0 0 0 1 0 1/2 0 -1/6]