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\begin{equation*}
\begin{flalign*}
 &\frac{dy}{dx}&=\frac{2-x}{y}\Longrightarrow ydy=(2-x)dx\Longrightarrow \int ydy=\int 2-x dx\\
&  &\Longrightarrow\frac{y^2}{2}=2x-\frac{x^2}{2}\Longrightarrow y^2=4x-x^2.\\
\end{flalign*}
\end{equation*}


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