Question

x+y=3
x2+2xy+2y2=13
Система уравнений

Answer 1

$left { {x+y=3} atop { x^{2} +2xy+2y^{2}=13} right. \ left { {{x=3-y} atop {(3-y)^{2}+2y(3-y)+2y^{2}=13}} right. \ 9-6y+y^{2}+6y-2y^{2}+2y^{2}=13 \ y^{2}= 4 \ y_{1,2}= + - 2 \ x_{1}= 3-2 \ x_{1}=1 \ x_{2}= 3+2 \ x_{2}=5$
Ответ: (1;2) и (5; -2).