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