## Precalculus: Mathematics for Calculus, 7th Edition

$-\frac{2(\sqrt 2-\sqrt 7)}{5}$
Multiply by conjugate radical: $\frac{2}{\sqrt 2+\sqrt 7}\times\frac{\sqrt 2-\sqrt 7}{\sqrt 2-\sqrt 7}$ Simplify using the Special Product Formula 1: $\frac{2(\sqrt 2-\sqrt 7)}{(\sqrt 2)^2-(\sqrt 7)^2}=\frac{2(\sqrt 2-\sqrt 7)}{2-7}=-\frac{2(\sqrt 2-\sqrt 7)}{5}$