1. Section 7.4 Adding and Subtracting Rational Expressions
Honors Algebra 2
Section 7.4
Adding and Subtracting Rational Expressions

2. Adding Fractions with the Same Denominator
Rule?

3. Try these!
#1 5 21𝑥 𝑥 #2 4𝑥 𝑥−5 − 3 𝑥−5 #3 7𝑥+1 3 − 𝑥+16 3

4. Adding Fractions with Different Denominators

5. You can do this using the “upside-down picnic table” method but this doesn’t give you the lowest common denominator.
= 24 18

6. Vintage math Find the least common multiple (LCM) of 35 and 45.
How can this be done?

7. With expressions as denominators, you always want the least common denominator.

8. Find the least common multiple of
6 𝑥 2 −54 𝑎𝑛𝑑 9𝑥 2 −54𝑥+81
1) Factor
2) Take one of every factor-highest power of
common factors

9. Steps For Adding (or Subtracting) with Different Denominators
LCM of denominators
Parentheses around numerators
Rewrite fractions with LCM
Write as a single fraction
Simplify

10. For Acronym Lovers
Let Parents Rule With Sanity

11. More Acronyms

12. Find the sum or difference.
# 𝑥 2 + 𝑥 𝑥 2 +𝑥
#2 5𝑥−1 𝑥 2 −3𝑥+2 − −2𝑥−1 2𝑥−4

13. Complex fraction- a fraction that contains a fraction in the numerator or denominator or both

14. For complex fractions-
Write the numerator and denominator as a single fraction
The fraction bar means divide
Divide numerator by the denominator

15. Simplify 6 𝑥−2 1 𝑥−2 + 3 𝑥

16. Assignment #32
Pg #3-25 odd, odd