\[\sqrt{\left( x^{2} - 11x + 24 \right)^{- 1}} =\]
\[= \sqrt{\frac{1}{x^{2} - 11x + 24}}\]
\[ООФ:\ \ \ x^{2} - 11x + 24 > 0\]
\[D = 121 - 96 = 25\]
\[x_{1} = \frac{11 + 5}{2} = 8;\ \ \ \ \ \]
\[x_{2} = \frac{11 - 5}{2} = 3.\]
\[Ответ:( - \infty;3) \cup (8;\ + \infty).\]