Решите, систему пжжжжжжж
\left \{ {{8x-9y-21=0} \atop {3x-2y-12=0}} \right. \left \{ {{11x-11y=33} \atop {3x-2y-12=0}} \right. \left \{ {{x-y=3} \atop {3x-2y-12=0}} \right. \left \{ {{x=3+y} \atop {3(3+y)-2y=12}} \right. \left \{ {{x=3+y} \atop {9+3y-2y=12}} \right.