\[\boxed{\text{1255.}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[1)\ \left\{ \begin{matrix} 2x - y = 6 \\ 3x + y = 4 \\ \end{matrix} \right.\ ( + )\]
\[5x = 10.\]
\[2)\ \left\{ \begin{matrix} 4x - 7y = 8 \\ 6y - 4x = 1 \\ \end{matrix} \right.\ \]
\[\left\{ \begin{matrix} 4x - 7y = 8\ \ \ \\ - 4x + 6y = 1 \\ \end{matrix} \right.\ ( + )\]
\[- y = 9.\]