Are you using Wolfram|Alpha? Please see the examples section for example of how to do Integrals
First, you will want to rewrite this so that the dx and the dy are both at the right side of the equation. Currently the dx is to the left of an integral. If you aren't sure how to do this, I would ask your math teacher.
http://www.wolframalpha.com/examples/Integrals.html
