1. Adding and Subtracting Rational Expressions
Section
7.3
Adding and Subtracting Rational Expressions

2. Rational Expressions
Adding and Subtracting Rational Expressions with Common Denominators
If are rational expressions, then
and
To add or subtract rational expressions, add or subtract numerators and place the sum or difference over the common denominator.

3. Example
Add:

4. Example
Subtract:

5. Example
Add.

6. Example
Subtract:

7. Adding or Subtracting Rational Expressions with Unlike Denominators
Step 1: Find the LCD of all the rational expressions.
Step 2: Rewrite each rational expression as an equivalent expression whose denominator is the LCD found in Step 1.
Step 3: Add or subtract numerators and write the sum or difference over the common denominator.
Step 4: Simplify or write the rational expression in lowest terms.

8. Example
Add.

9. Example
Perform the indicated operation.

10. Example
Subtract:

11. Example
Subtract:

12. Example
Subtract:

13. Example
Add: