Rationalize the denominator. 

$-\(\frac{5}{2\sqrt7}\)$

Rationalize the denominator.

$\(\frac{6+\sqrt{x}\)}{-\(\sqrt{x}\)}$

Rationalize the denominator and simplify the radical expression.

$\(\frac{\sqrt7}{5-\sqrt6}\)$

Rationalize the denominator and simplify the radical expression.

$\(\frac{2-\sqrt3}{2+\sqrt3}\)$

CONCEPT PREVIEW Perform the operations mentally, and write the answers without doing intermediate steps. √6 • √6

CONCEPT PREVIEW Perform the operations mentally, and write the answers without doing intermediate steps. (√28 - √14) (√28 + √14)

Find each square root. See Example 1. √100

Find each square root. See Example 1. -√256