\(\hept{\begin{cases}x^2-2y^2=2x+y\left(1\right)\\y^2-2x^2=2y+x\left(2\right)\end{cases}}\)
\(\left(1\right)-\left(2\right)\)
\(\Leftrightarrow3x^2-3y^2=x-y\)
\(\Leftrightarrow\left(x-y\right)\left(3x+3y-1\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x-y=0\\3x+3y-1=0\end{cases}}\)
TH1: x=y => x2 - 2x2 =2x+x => -x2 - 3x=0
\(\Leftrightarrow\orbr{\begin{cases}x=0\\x=-3\end{cases}}\)
Th2: (làm tương tự TH1)