Rational Expressions
Adding and Subtracting:
In order to add and subtract fractions you must have a common denominator, well the same concept applies when adding and subtracting fractions with variables in the denominator:
Multiplying and Dividing:
While it is required that you have a common denominator when multiplying or dividing, you don't have to when multiplying fractions.
Simply multiply the numerators together and the denominators together and then cancel out.
Dividing Fractions with Fractions:
You simply flip the bottom fraction upside down and then multiply and cancel out.
x+5
x+5 2x
2(x+5)
---- ----- * = -------
x
x
x-5 (x-5)
------ =
x-5
----
2x