## Precalculus (6th Edition) Blitzer

$\sqrt{10}+\sqrt{2}$
The given expression's denominator can be rationalized by multiplying the conjugate denominator's conjugate to both the numerator and the denominator. RECALL: The conjugate of $\sqrt{a} - \sqrt{b}$ is $\sqrt{a}+\sqrt{b}$. Thus, the conjugate of the denominator is $\sqrt{10}+\sqrt{2}$. Thus, to rationalize the denominator of the given expression, multiply the numerator and the denominator by $\sqrt{10}+\sqrt{2}$.