What is the indefinite integral of 1 over u du? That's just going to be equal to the natural log of the absolute value, and we use the absolute value so it'll be defined even for negative u's. It actually does work out, and I'll do another video where I show you that it definitely does. The natural log of the absolute value of u, and then we might have had a constant there that was lost when we took the derivative. That's essentially our answer in terms of u, but now we need to unsubstitute the u. What happens when we unsubstitute the u? Then we are left with, this is going to be equal to the natural log of the absolute value of, well u is x to the fourth plus 7.