3 Halle todas las $f:R^+ \rightarrow R^+$ tales que $f(f(x) + y)f(x) = f(xy + 1)\ \ \forall x, y \in R^+$ @below: https://artofproblemsolving.com/community/c6h2254883_2020_imoc_problems Quote: Feel free to start individual threads for the problems as usual