Question

помогите решить №2!
срочно Алгебра

Answer 1

$\displaystyle \left \{ {{4x-y=9} \atop {3x+7y=-1}} \right.\\ \\\left \{ {{y=-9+4x} \atop {3x+7y=-1}} \right. \\\\3x+7(-9+4x)=-1\\x=2\\y=-9+4*2\\y=-1\\(x,y)=(2,-1)$