I'm having a little trouble computing the inverse of the Möbius transform in $\mathbb{R^n}$, as outlined here in "higher dimensions". I assume it exists because it goes on to say that it forms a group.
$$f(x) = b + \frac{\alpha A(x-a)}{|x-a|^2}, \quad x, a, b \in \mathbb{R}^n, \alpha \in \mathbb{R}$$
Where $A$ is an orthogonal matrix. It seems like it would be elementary, but not quite sure how to deal with the norm, and scouring the literature no one seems to bother computing it.