\[\left\{ \begin{matrix} y = - x\ \ \ \ \\ y = x - 8 \\ \end{matrix} \right.\ \]
\[- x = x - 8\]
\[2x = 8\]
\[x = 4\]
\[y = - x\]
\[y = - 4\]
\[Ответ:\ \ (4;\ - 4).\]