2. Adding & Subtracting Rational Expressions The procedure for adding and subtracting rational expressions is the same as it is with numerical fractions......before you can add or subtract, you must have the lowest common denominator. (LCD)

3. Example #1: a. b. *In both of these examples the denominator is the same, so just add or subtract the numerator.

4. Adding or subtracting with common denominators requires that you only combine the numerators. What if you had different denominators? In the next case you will need to find a common denominator for the two rational expressions and then add or subtract.

5. Example #2: To prepare for this fraction, it would be helpful to go ahead and factor the denominators. The LCD for two (or more) algebraic rational expressions must contain each factor of the denominator raised to its highest power.

6. Example #3:

7. Example #4:

9. Finish up…