Question

розв'яжіть, будь ласка​

Answer 1

$\left\{\begin{matrix}x^2-2xy+y^2=9\\ 4x^2+xy+4y^2=18\end{matrix}\right.\\x^2-2xy+y^2=9\Leftrightarrow \left ( x-y \right )^2=9\\1. \ \ x=y+3\Rightarrow 4(y+3)^2+y(y+3)+4y^2-18=0\\9y^2+27y+18=0\Rightarrow y=\left \{ -2;-1 \right \}\Rightarrow x=\left \{ 1;2 \right \}\\2. \ \ x=y-3\Rightarrow 4(y-3)^2+y(y-3)+4y^2-18=0\\9y^2-27y+18=0\Rightarrow y=\left \{ 1;2 \right \}\Rightarrow x=\left \{ -2;-1 \right \}$