## Key Concepts

- Rational expressions can be simplified by canceling 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

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