## Key Concepts

**To Simplify a Rational Expression by Writing it as Division**- Simplify the numerator and denominator.
- Rewrite the complex rational expression as a division problem.
- Divide the expressions.

**To Simplify a Complex Rational Expression by Using the LCD**- Find the LCD of all fractions in the complex rational expression.
- Multiply the numerator and denominator by the LCD.
- Simplify the expression.

## Glossary

### complex rational expression

A complex rational expression is a rational expression in which the numerator or denominator contains a rational expression.