Решите систему уравнений: 3m-2n=9; 5m+n=15.

\[\left\{ \begin{matrix} 3m - 2n = 9\ \ \ \ \ \ \ \ \ \\ 5m + n = 15\ \ | \cdot 2 \\ \end{matrix} \right.\ \]

\[\left\{ \begin{matrix} 3m - 2n = 9\ \ \ \ \ \\ 10m + 2n = 30 \\ \end{matrix} \right.\ ( + )\]

\[13m = 39\]

\[m = 9;\ \]

\[n = 15 - 5m = 15 - 45 = - 30.\]

\[Ответ:(9;\ - 30).\]