Решите систему уравнений 7x-y=10; 5x+2y=-1.

\[\left\{ \begin{matrix}
7x - y = 10\ \ | \cdot 2\ \\
5x + 2y = - 1\ \ \ \ \ \ \ \\
\end{matrix} \right.\ \]

\[\left\{ \begin{matrix}
14x - 2y = 20 \\
5x + 2y = - 1\ \\
\end{matrix} \right.\ \ ( + )\]

\[19x = 19\]

\[x = 1.\]

\[y = 7x - 10 = 7 \cdot 1 - 10 = - 3.\]

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

\[Ответ:(1;\ - 3).\]