\[\frac{2a^{2} - 5a + 4}{(a - 2)^{2}} - \frac{a - 3^{\backslash a - 2}}{a - 2} =\]
\[= \frac{2a^{2} - 5a + 4 - (a - 3)(a - 2)}{(a - 2)^{2}} =\]
\[= \frac{2a^{2} - 5a + 4 - a^{2} + 2a + 3a - 6}{(a - 2)^{2}} =\]
\[= \frac{a^{2} - 2}{(a - 2)^{2}}\]