2000017413

Consider the matrices $$A=\left(\begin{array}{ccc}1& 0& 0\\ -1& 1& 1\\ 2& 1& 0\end{array}\right),B=\left(\begin{array}{ccc}-1& 1& 0\\ 0& 1& 1\\ 1& 1& -1\end{array}\right).$$ For which matrix $X$ holds $A\cdot B-X=B^2$?