\[x^{2} - y^{2} = 5\]
\[(x - y)(x + y) = 5\]
\[\left\{ \begin{matrix}
x - y = \pm 1 \\
x + y = \pm 5 \\
\end{matrix} \right.\ \ \ \ \ \ или\ \ \]
\[\text{\ \ }\left\{ \begin{matrix}
x - y = \pm 5 \\
x + y = \pm 1 \\
\end{matrix} \right.\ \]
\[\left\lbrack \begin{matrix}
\left\{ \begin{matrix}
x = \pm 3 \\
y = \pm 2 \\
\end{matrix} \right.\ \\
\left\{ \begin{matrix}
x = \pm 3 \\
y = \pm 2 \\
\end{matrix} \right.\ \\
\end{matrix} \right.\ \]