1. Section 7.2
Adding and Subtracting Rational Expressions

2. Rational  Fractional!
So, we will need Common Denominators before we can Add or Subtract!!!
Remember to SIMPLIFY the answers!!!
Add or Subtract:
x – 3y x – 5y
3x – 2y x – 2y
r2 – 3r r – 15
r2 – 6r r2 – 6r + 9

3. To find the LCD:
Factor all denominators completely. (Prime factorization)
Write a product that contains each unique factor the greatest number of times that that factor occurs.
Then, multiply each rational expression by whatever is needed to achieve the common denominator.
Add or Subtract, and simplify the answer.

4. Add or Subtract 1. 11 + 13 2. y - y 12a6b3 18a4b5 y – 3 y – 4n
n2 + 14n n + 7
v2 + 4v
v2 + 8v v + 12
5. x – 5y x – 6y
x – y y – x