\[\frac{x^{2}}{x - 5} + \frac{4x}{5 - x} = \frac{5}{x - 5}\]
\[\frac{x^{2}}{x - 5} - \frac{4x}{x - 5} - \frac{5}{x - 5} = 0\]
\[\frac{x^{2} - 4x - 5}{x - 5} = 0\ \ \ \ \ \ \ \ x \neq 5\]
\[x^{2} - 4x - 5 = 0\]
\[D = ( - 4)^{2} - 4 \cdot 1 \cdot ( - 5) =\]
\[= 16 + 20 = 36\]
\[x_{1} = \frac{4 + \sqrt{36}}{2} = \frac{4 + 6}{2} = \frac{10}{2} =\]
\[= 5\ (не\ подходит)\]
\[x_{2} = \frac{4 - \sqrt{36}}{2} = \frac{4 - 6}{2} = \frac{- 2}{2} =\]
\[= - 1.\]
\[Ответ:\ - 1.\]