$x,n,m >1$ and $x,n,m \in \mathbb{Z}$
I've tried to solve it myself, but I'm getting nowhere, so apologies if it's an irritatingly basic question.
Whilst I'm on it, is it true that $y^x \ne m^n+1$ ($y>1, y \in \mathbb{Z}$)? There's probably a glaringly obvious counterexample I'm overlooking.