\[\frac{x^{2} - 25}{2 - \sqrt{x - 1}} =\]
\[= \frac{(x - 5)(x + 5)\left( 2 + \sqrt{x - 1} \right)}{\left( 2 - \sqrt{x - 1} \right)\left( 2 + \sqrt{x - 1} \right)} =\]
\[= \frac{(x - 5)(x + 5)\left( 2 + \sqrt{x - 1} \right)}{4 - x + 1} =\]
\[= - (x + 5)(2 + \sqrt{x - 1})\]