I wasn't sure where to put this, but here goes.
is a formula we have been given.
We have been told that the denominator is a factor when x is prime and we're expected to prove/show that to be the truth.
It works experimentally (substituting numbers) but I can't actually find a proper proof.
Best I could come up with is:
Let it equal so that therefore b is a factor of a (a=by, y is an integer)
That leads me to subsitute them back and get:
which simplifies to give y, which is an integer.
Any proper proofs?