# Adding rational expressions with different denominators 4

Taught by YourMathGal
• Currently 4.0/5 Stars.
6049 views | 1 rating
Part of video series
Meets NCTM Standards:
Lesson Summary:

This lesson teaches how to add and subtract algebraic fractions by finding the least common denominator. The instructor demonstrates a few examples and urges students to factor the denominator and then multiply both the numerator and denominator to get a common denominator. Then, each fraction can be put over the common denominator, and the numerators can be simplified by adding like terms. Finally, the instructor encourages students to factor the numerator to check if anything cancels out.

Lesson Description:

Shows how to add and subtract algebraic fractions by getting a common denominator.

More free YouTube videos by Julie Harland are organized at http://yourmathgal.com

Questions answered by this video:
• How do you add and subtract rational expressions with unlike denominators?
• How do you add 7/(2m + 20) + 70/(m^2 - 100)?
• How do you add (2x + 5)/(x - 3) + 5x/(2x + 1)?
• How do you subtract 3/(x + h) - 1/x?
• #### Staff Review

• Currently 4.0/5 Stars.
This lesson just shows some more examples of adding and subtracting rational expressions with different denominators. The problems continue to increase in difficulty as the lessons goes on. Perhaps this series could be used on successive days to help test your skills and learn a bit more each day. In some problems, the result of the addition or subtraction can be simplified to get the final result.