Adding and subtracting rational expressions

4 videos
5 skills
Learn how to add and subtract rational expressions. Like multiplication and division, this skill has a remarkable affinity to adding and subtracting fractions!

Add and subtract rational expressions with the same denominator

PRACTICE PROBLEMS
Ease into the realm of rational-expression-addition-and-subtraction by first working with expressions that have the same denominator.

How to add two rational expressions with different denominators (example)

VIDEO 2:44 minutes
Sal rewrites a/b+c/d as a single rational expression.

Add and subtract rational expressions with relatively prime denominators

PRACTICE PROBLEMS
Add and subtract rational expressions with relatively prime denominators by manipulating them to have the same denominators.

How to find the least common multiple of two numbers (example)

VIDEO 4:16 minutes
Sal finds the lcm (least common multiple) of 12 and 36, and of 12 and 18. He shows how to do that using the prime factorization method, which is a just great!

How to find the least common multiple of two numbers with repeating factors (example)

VIDEO 2:35 minutes
Sal finds the lcm (least common multiple) of 25 and 30.

Least common multiple

PRACTICE PROBLEMS
Find the lcm (least common multiple) of pairs of integers.

Add and subtract rational expressions with factored denominators

PRACTICE PROBLEMS
Add and subtract rational expressions with factored denominators by manipulating them to have the same denominators.

How to subtract rational expressions by finding the least common multiple (example)

VIDEO 4:36 minutes
Sal performs the following subtraction and simplifies the result: (a-2)/(a+2) - (a-3)/(a^2+4a+4).

Add and subtract rational expressions by finding the least common multiple

PRACTICE PROBLEMS
Master the skill of rational-expression-addition-and-subtraction by working with expressions whose denominators aren't factored and may or may not have shared factors.