27

May

2018

May

2018

## Week 15 – Adding and Subtracting Rational Expressions

categories: Math 11, Uncategorized

This week we learned how to add and subtract rational expressions. These are a bit harder than multiplying and dividing because the denominator has to be the same throughout the expression.

Steps to simplify:

- determine lowest common denominator (LCD)
- rewrite each fraction as an equivalent fraction with LCD
- Combine numerators by adding/subtracting
- reduce if possible

For example: where “x” cannot equal 0 or 4.

- For this expression, the least common denominator would be because neither denominator can be simplified any farther or multipled to create a common denominator, so we multiple the two denominators together to create one LCD.
- Since we’re multiplying the bottom, we also have to do the same to the top, so the equation becomes: .
- This simplifies to
- The final simplified expression will be