1. Sums and Differences of Rational Expressions
Objective: to add and subtract rational expressions

2. Rules for adding and subtracting fractions
Find the least common denominator (LCD) of the fractions (that is the least common multiple of the denominators.)
Express each fraction as an equivalent fraction with the LCD as the denominator
Add or subtract and then simplify.

3. Examples Simplify The LCM of 5 = 5 • 1 and 15 = 5 • 3 is 15
2. multiplying by 1 will not change a number 3.

4. Example with monomials
Simplify
The LCM of 3x2y, 12x, and 8y2 is 24x2y2 3.

5. Example with Polynomials
Simplify
Factor
The LCM is (x + 3)(x – 3)(x – 1)

6. Be careful, its not done yet

7. factor

8. Try These! Simplify 1. 2. 3. 4. 1. 2. 3. 4.
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