\[\frac{\sqrt{5x - 2x^{2}}}{x^{2} - 1}\]
\[\left\{ \begin{matrix} 0 \leq x \leq 2,5 \\ x \neq \pm 1\ \ \ \ \ \ \ \ \\ \end{matrix} \right.\ \]
\[D(y) = \lbrack 0;1) \cup (1;2,5\rbrack.\]