\[\ \frac{x - 13}{x + 8} > 0\]
\[x - 13 = 0\ \ \ \ \ \ x + 8 = 0\]
\[x = 13\ \ \ \ \ \text{\ \ }\ \ \ \ \ \ \ x = - 8\ \]
\[Ответ:\ x \in ( - \infty; - 8) \cup (13; + \infty).\]