Answer :
[tex] \left \{ {{2x+7y=1} \atop {x+5y=2\ \ |*(-2)}} \right. \\\\
\left \{ {{2x+7y=1} \atop {-2x-10y=-4}} \right. \\+----\\elimination\ method\\\\
-3y=-3\ \ \ | divide\ by\ -3\\
y=1\\\\
x=2-5y=2-5=-3\\\\
solution:\\ \left \{ {{y=1} \atop {x=-3}} \right. [/tex]
