Fie [tex]A=\left[\begin{array}{ccc}1&-1\\2&2\end{array}\right][/tex] si [tex]B=\left[\begin{array}{ccc}1&1&\\a&b&\end{array}\right][/tex]

Aflati a,b ∈R stiind ca [tex]B^{-1} = \left[\begin{array}{ccc}2&-1&\\-1&1&\end{array}\right][/tex]