So imagine doing this. Let's rewrite our original integral. The original, so let me draw a little arrow here just to go around that aside. We could write our original integral as being equal to the integral of 1 7th times seven times the square root of seven x plus nine dx. And if we want to, we could take the 1 7th outside of the integral. We don't have to, but we could rewrite this as 1 7th times the integral of seven times the square root of seven x plus nine dx. So now if we set u equal to seven x plus nine, do we have its derivative laying around?