[tex] Sa~se~rezolve~ecuatia~: ~\sigma\* x=x\sigma~.\\ \\ \sigma=\[
\bigl(\begin{smallmatrix}
1 & 2 & 3 & 4 & 5 \\
3 & 1 & 4 & 5 & 2
\end{smallmatrix}\bigr) [/tex]