15. Rational Expressions and Equations

Add the following and simplify the sum if possible.

$\frac{x+1}{3x}+\frac{2x-1}{3x}$

Add the following and simplify the sum if possible.

$\frac{x^2-4}{x^2-x-6}+\frac{x+2}{x^2-x-6}$

Subtract the following and simplify the difference if possible.

$\frac{x+5}{4x}-\frac{2x-1}{4x}$

Subtract the following and simplify the difference if possible.

$\frac{x^2-4}{x^2-x-6}-\frac{x+2}{x^2-x-6}$