Решите систему уравнений: 5x+y=14; 2x-3y=9.

\[\left\{ \begin{matrix}
5x + y = 14\ \ \ \ \ | \cdot 3 \\
2x - 3y = 9\ \ \ \ \ \ \ \ \ \ \ \ \\
\end{matrix} \right.\ \text{\ \ \ \ \ \ \ \ }\]

\[\left\{ \begin{matrix}
15x + 3y = 42 \\
2x - 3y = 9\ \ \ \ \ \\
\end{matrix} \right.\ \text{\ \ \ }( + )\]

\[17x = 51\]

\[x = 3.\]

\[\left\{ \begin{matrix}
y = 14 - 5x \\
x = 3\ \ \ \ \ \ \ \ \ \ \ \ \ \\
\end{matrix} \right.\ \text{\ \ \ \ \ \ \ \ \ \ }\left\{ \begin{matrix}
y = 14 - 15 \\
x = 3\ \ \ \ \ \ \ \ \ \ \ \ \ \\
\end{matrix} \right.\ \text{\ \ \ \ \ \ \ }\]

\[\left\{ \begin{matrix}
y = - 1 \\
x = 3\ \ \ \\
\end{matrix} \right.\ \]

\[Ответ:(3; - 1).\]