## 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