## Algebra and Trigonometry 10th Edition

-x-5, $x\ne5$
Expression : $\frac{x^{2}-25}{5-x}=\frac{-(5-x)(x+5)}{5-x}=-(x+5)=-x-5$ with x≠5 as x=5 would make the denominator in the original expression zero and division by 0 is not allowed.