0. Review of College Algebra

Add or subtract, as indicated. See Example 4. (1/(x + z)) + (1/(x - z))

Rationalize the denominator. 

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

Rationalize the denominator and simplify the radical expression.

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

Find the square of each radical expression. See Example 2. -√19