## Key Concepts

- Rational expressions can be simplified by cancelling common factors in the numerator and denominator.
- We can multiply rational expressions by multiplying the numerators and multiplying the denominators.
- To divide rational expressions, multiply by the reciprocal of the second expression.
- Adding or subtracting rational expressions requires finding a common denominator.
- Complex rational expressions have fractions in the numerator or the denominator. These expressions can be simplified.

## Glossary

**least common denominator** the smallest multiple that two denominators have in common

**rational expression** the quotient of two polynomial expressions