# How do you simplify (25-x^2)/(x^2-10x+25)?

$- \frac{x + 5}{x - 5}$
$\frac{25 - {x}^{2}}{{x}^{2} - 10 x + 25} = \frac{\left(5 - x\right) \left(5 + x\right)}{\left(x - 5\right) \left(x - 5\right)}$
$= \frac{\textcolor{b l u e}{- \cancel{\left(x - 5\right)}} \left(5 + x\right)}{\cancel{\left(x - 5\right)} \left(x - 5\right)}$
$= - \frac{x + 5}{x - 5}$