Suppose I know the value of $n$ (where $n = pq$), and I also know $k = p-q$. How can I efficiently factor $n$?
Note that I don't know $p$ or $q$.
EDIT: Thank you for your answers. I understand that I could use basic algebra but would it be efficient to use that if $n$ was large? For example, if $n = 59305397$?