Question

Система уравнений
помогите пожалуйста

Answer 1

$\displaystyle 1)\left \{ {{x+3y=7} \atop {2x-y=-7}} \right.\\\\ \left \{ {{x=7-3y} \atop {2x-y=-7}} \right. \\\\ 2(7-3y)-y=-7\\y=3\\x=7-3*3\\x=-2\\(x,y)=(-2,3)\\\\ 2)\left \{ {{3x-y=2} \atop {6x-2y=1}} \right.\\\\ \left \{ {{y=-2+3x} \atop {6x-2y=1}} \right.\\\\ 6x-2(-2+3x)=1\\x\in\phi\\(x,y) \in\phi$