\[5\sqrt{x} - \frac{5}{\sqrt{x}} = 24\]
\[Пусть\ \ t = \sqrt{x}:\]
\[5t - \frac{5}{t} = 24\]
\[5t^{2} - 24t - 5 = 0\]
\[D = 576 + 100 = 676 = 26²\]
\[t = \frac{24 \pm 26}{10}\]
\[t = 5\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ t = - 0,2\]
\[\sqrt{x} = 5\ \ \ \ \ \ \ \ \ \ \ \sqrt{x} = - 0,2\]
\[x = 25\ \ \ \ \ \ \ \ \ \ \ \ \ \ \varnothing\]
\[Ответ:25.\ \]