When subtracting rational expressions, first make the denominators common.

Example:

*Remember whatever you do to the bottom you have to do to the top!*

Next, combine everything on the numerator (top)

After you have simplified the top, then you can put it over the denominator that we have just made common between the two rational expressions.

Now, Just add the numerators together and we are left with:

Because we cannot simplify any more, that is our final answer!

Adding rational expressions is the same processes.

If the expressions already have the same denominator then the problem becomes even more simple!

Example:

Because the denominators are the same, we can just add the numerators together

We are left with 9x and we can just put that on top of our denominator. Then we are left with:

Because we cannot simplify any further, this is our final answer!