Question

Giải hệ \(\left\{{}\begin{matrix}x^2-2y^2+xy-3x+3y=0\\x^2+y^2+xy=3\end{matrix}\right.\)

Answer 1

\(x^2-2y^2+xy-3x+3y=0\)

\(\Leftrightarrow\left(x-y\right)\left(x+2y\right)-3\left(x-y\right)=0\)

\(\Leftrightarrow\left(x-y\right)\left(x+2y-3\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=y\\x=3-2y\end{matrix}\right.\)

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