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

Ответ:

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

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

\[19x = 19\]

\[x = 1.\]

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

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

\[Ответ:(1;\ - 3).\]