\(\Leftrightarrow\left\{{}\begin{matrix}3x\left(2x-y\right)+x+y-1=0\\x^2+y^2=1\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}3x\left(2x-y\right)-\left(2x-y\right)+3x-1=0\\x^2+y^2=1\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}\left(3x-1\right)\left(2x-y\right)+3x-1=0\\x^2+y^2=1\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}\left(3x-1\right)\left(2x-y+1\right)=0\\x^2+y^2=1\end{matrix}\right.\)
\(\Leftrightarrow...\)