. - The key here is pulling the constant out, before doing u substitution.
. ?? What is the next step? Somehow we need to get rid of that constant of 1, and
Note: The answer to this problem is But do we get there?
Unfortunately, (it breaks my heart to tell you this), but the answer (you have) is wrong!
I'll give you a critical step.
Factor out in the denominator
Then use the substitution
See where that gets you =)