$\left\{{{2x+4y=2}\atop{3x-7y=16}}\right.$
$\Leftrightarrow \left\{{{6x+12y=6}\atop{6x-14y=32}}\right.$
$\Leftrightarrow \left\{{{26y=-26}\atop{6x-14y=32}}\right.$
$\Leftrightarrow \left\{{{y=-1}\atop{6x-14.(-1)=32}}\right.$
$\Leftrightarrow \left\{{{x=3}\atop{y=-1}}\right.$
$\Rightarrow (x;y)=(3; -1)$