I realize this is basic, but this little doubt has been around with me for quite a while:
I have this:
I need it to end up with this shape:
At first, I thought "well, I simply remove the $(2n+3)$ from the numerator and from the denominator and done!", but I would like to know if there are any other steps in the middle I am "jumping" by doing so.
Basically, I would like to do it as "slowly" as possible (because my professor will want to during the tests...). Is there any small step I am missing?