Ta xét:
\(\left(x-5\right)\left(y-5\right)=25\Leftrightarrow x-5=y-5=5\Leftrightarrow x=y=10\)
\(x-5=y-5=-5\Leftrightarrow x=y=0\)
\(\left\{{}\begin{matrix}x-5=1\\y-5=25\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=6\\y=30\end{matrix}\right.\)
\(\left\{{}\begin{matrix}x-5=-1\\y-5=-25\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}y=4\\y=-20\end{matrix}\right.\)
\(\left\{{}\begin{matrix}x-5=25\\y-5=1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}y=30\\y=6\end{matrix}\right.\)
\(\left\{{}\begin{matrix}x-5=-25\\y-5=-1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}y=-20\\y=4\end{matrix}\right.\)
Vậy \(\left(x,y\right)\in\left\{\left(10;10\right),\left(0;0\right),\left(6;30\right),\left(4;-20\right),\left(30;6\right),\left(-20;4\right)\right\}\)