\[а)\ \left\{ \begin{matrix} y = - x + 2 \\ y = x\ \ \ \ \ \ \ \ \ \ \\ \end{matrix} \right.\ \]
\[б)\ \left\{ \begin{matrix} y = 2 - 2x \\ y = 4\ \ \ \ \ \ \ \ \ \ \\ \end{matrix} \right.\ \]
\[в)\ \left\{ \begin{matrix} y = - \frac{2}{3}x - 2 \\ y = - \frac{2}{3}x + 2 \\ \end{matrix} \right.\ \]