Hi Luis. I'm interpreting your question as this:

I think what you must be having trouble with is sorting out that fraction.

If it was a simpler fraction I think you would find it easier to see what to do. Let's just say it is A over B. You would do this:

Right? Well, it is no different with a question like yours, it is just that the fraction LOOKS harder -- the same steps are actually involved.

For example, here is a question a lot like yours:

To get rid of the fraction, you multiply both sides by the denominator, just like we did in A/B above when we multiplied by B:

Then you can finish the solution in the usual way:

Now that you have a close example, follow this model and solve your question.

Hope this helps,
Stephen La Rocque.