1. Adding and Subtracting Rational Expressions
Essential Questions
How do we add and subtract rational expressions?
How do we simplify complex fractions?
Holt McDougal Algebra 2
Holt Algebra 2

2. Example 1: Add and Subtract Rational Expressions
Add. Identify any x-values for which the expression is undefined. x
x + 2 + –8
x2 – 4
Factor the denominators.
The LCD is (x + 2)(x – 2).
Rewrite as one fraction.
Factor the numerator.
Undefined at x = –2 and x = 2

3. Example 2: Add and Subtract Rational Expressions
Subtract. Identify any x-values for which the expression is undefined. - + +
Change the signs for subtraction.
Factor the denominators.
The LCD is (x + 1)(x - 1).
Rewrite as one fraction.
Simplify the numerator.
Factor the numerator.
Undefined at x = –1 and x = 1

4. Example 3: Add and Subtract Rational Expressions
Subtract. Identify any x-values for which the expression is undefined. - +
Change the signs for subtraction.
Treat like a mixed number
Rewrite as one fraction.
Simplify the numerator.
Undefined at x = –5

5. Example 4: Add and Subtract Rational Expressions
Subtract. Identify any x-values for which the expression is undefined. - +
Change the signs for subtraction. +
Treat like a mixed number
Rewrite as one fraction.
Simplify the numerator.
Factor the numerator.
Undefined at x = 3

6. Lesson 6.3 Practice C