Question

РЕШИТЕ СИСТЕМУ УРАВНЕНИЙ МЕТОДОМ ПОДСТАНОВКИ:
{7x-y=22
{8x+7y=17

{x+2y=10
{8x+5y=14

ПОМОГИТЕ ПОЖАЛУЙСТА

Answer 1

$\displaystyle 1)\left \{ {{7x-y=22} \atop {8x+7y=17}} \right. \\\\\left \{ {{y=-22+7x} \atop {8x+7y=17}} \right. \\\\8x+7(-22+7x)=17\\x=3\\y=-22+7*3\\y=-1\\(x,y)=(3,-1)\\\\2)\left \{ {{x+2y=10} \atop {8x+5y=14}} \right. \\\\\left \{ {{x=10-2y} \atop {8x+5y=14}} \right. \\\\8(10-2y)+5y=14\\y=6\\x=10-2*6\\x=-2\\(x,y)=(-2,6)$