Fractions with Different Denominators
You can also add and subtract fractions containing different variables. For fractions with different denominators that are going to be added or subtracted together, you calculate the common denominator in the normal way.
Example 1
Write as a single fraction
The variables just represent numbers. Since is one of the denominators and is the other, then is the common denominator. You find this by expanding the first fraction by , and the other fraction by :