Question

Виконати способом додавання​

Answer 1

$\displaystyle \left \{ {{7x+2y=-3|*2} \atop {-14x+3y=20}} \right. \\+\left \{ {{14x+4y=-6} \atop {-14x+3y=20}} \right. \\-----------\\7y=14;y=14:7;y=2.\\-14x+3*2=20;\\-14x+6=20;\\-14x=20-6;\\-14x=14;\\x=14:(-14);\\x=-1.$

$Otvet:(-1;2).$