I am trying to do an inverse of the following matrix but somehow I can't work it out.

The given matrix is this:

I added the I matrix to that :Code:1 1 0 1 1 1 2 1 1

and started to reducing to upper triangular form:Code:1 1 0 | 1 0 0 1 1 1 | 0 1 0 2 1 1 | 0 0 1

I tried

Row2 = Row2 - Row1

Row3 = Row3 - 2Row1

but this was the result

and I got stuck there.Code:1 1 0 | 1 0 0 0 0 1 | -1 1 0 0 -1 1| -2 0 1

Isit perhaps because I am doing something wrong?