Question 119
Find all functions $f: \mathbb{R} \rightarrow \mathbb{R}$ such that for all $x, y \in \mathbb{R}$:
$$
(y+1) f(x)+f(x f(y)+f(x+y))=y
$$
$$
(y+1) f(x)+f(x f(y)+f(x+y))=y
$$
MathNet 2015-part-06 — 191 problems (EN–VI) Question 119
Math Olympiad Vault · MathNet 2015-part-06 — 191 problems (EN–VI)