## College Algebra 7th Edition

$\displaystyle\frac{x-4\sqrt{x}+4}{x-4}$
We multiply the numerator and denominator by $\sqrt{x}-2$ and use the fact that $(a-b)(a+b)=a^2-b^2$ to simplify: $\displaystyle \frac{\sqrt{x}-2}{\sqrt{x}+2}=\frac{\sqrt{x}-2}{\sqrt{x}+2}*\frac{\sqrt{x}-2}{\sqrt{x}-2}=\frac{(\sqrt{x}-2)(\sqrt{x}-2)}{x-4}=\frac{x-4\sqrt{x}+4}{x-4}$