\left \{ {{3x+12y-4x-4x-2y=0} \atop
{7x-35y-3x-12y-27=0}} \right.
\left \{ {{10y-5x=0} \atop
{4x-47y-27=0}} \right.
\left \{ {{x=2y} \atop
{-39y=27}} \right.
\left \{ {{y=-\frac{9}{13}} \atop
{x=1+\frac{5}{13}}} \right.
Ответ:(-\frac{9}{13};1+\frac{5}{13}).