\[\left\{ \begin{matrix}
y + x = 0\ \ \ \ \ \\
2x + y = - 3 \\
\end{matrix} \right.\ \text{\ \ \ \ \ \ \ }\]
\[\left\{ \begin{matrix}
y = - x\ \ \ \ \ \ \ \ \ \ \\
y = - 2x - 3 \\
\end{matrix} \right.\ \]
\[y = - x\]
| \[x\] | \[0\] | \[1\] |
|---|---|---|
| \[y\] | \[0\] | \[- 1\] |
\[y = - 2x - 3\]
| \[x\] | \[0\] | \[1\] |
|---|---|---|
| \[y\] | \[- 3\] | \[- 5\] |

\[Ответ:( - 3;3).\]