\[\frac{x - 1}{2x^{2} - 5x + 2}\]
\[2x^{2} - 5x + 2 \neq 0\]
\[D = 25 - 16 = 9\]
\[x_{1} = \frac{5 + 3}{4} = 2;\ \ x_{2} = \frac{5 - 3}{4} = 0,5.\]
\[D(y) = ( - \infty;0,5) \cup (0,5;2) \cup (2; + \infty).\]