1. The problem statement, all variables and given/known data So, I have to integrate the following expression: (e^7x)/(e^(14x) + 9)dx 2. Relevant equations We are doing the section on 'integrating by u-substitution' right now, so that might help in finding a solution... 3. The attempt at a solution So, I tried a bunch of stuff - I tried u=7x, u=e^7x, u=14x, u=e^14x, u=x, etc. etc. and I can't get the right answer!!! I have been working on this problem for over an hour and am on the verge of tears!