Решите систему пожалуйста

б)

$\left \{ {{3x+y=4} \atop {2x-2y=0}} \right.\\\\\left \{ {{3x+y=4} \atop {x-y=0}} \right. \\\\\left \{ {{y=x} \atop {3x+x=4}} \right\\\\\left \{ {{4x=4} \atop {y=x}} \right.\\\\\left \{ {{x=1} \atop {y=1}}} \right.$

в)

$\left \{ {{3x+y=4} \atop {2x-2y=0}} \right.\\\\+\left \{ {{3x+y=4} \atop {x-y=0}} \right.\\------\\4x=4\\x=1\\y=x\\y=1$

Ответ : (1 ; 1)