Помогите пожалуйста, алгебра, 7 класс

$\left \{ {{x-4y=9} \atop {3x+2y=13}} \right.\\\\ \left \{ {{x=9+4y} \atop {3*(9+4y)+2y=13}} \right.\\\\ \left \{ {{x=9+4y} \atop {27+12y+2y=13}} \right.\\\\ \left \{ {{x=9+4y} \atop {14y=-14}} \right.\\\\ \left \{ {{y=-1} \atop {x=9+4*(-1)}} \right.\\\\ \left \{ {{y=-1} \atop {x=5}} \right.$
Ответ: (5 ; - 1)

$\left \{ {{2x+y=6} \atop {-4x+3y=8}} \right.\\\\ \left \{ {{y=6-2x} \atop {-4x+3*(6-2x)=8}} \right.\\\\ \left \{ {{y=6-2x} \atop {-4x+18-6x=8}} \right.\\\\ \left \{ {{y=6-2x} \atop {-10x=-10}} \right.\\\\ \left \{ {{x=1} \atop {y=6-2*1}} \right.\\\\ \left \{ {{x=1} \atop {y=4}} \right.$

Ответ: (1 ; 4)