Để 2n+9/n-2 là số tự nhiên thì \(\left\{{}\begin{matrix}2n+9⋮n-2\\n>2\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}2n-4+13⋮n-2\\n>2\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}n>2\\n-2\in\left\{1;-1;13;-13\right\}\end{matrix}\right.\Leftrightarrow n\in\left\{3;15\right\}\)