Question 171
Find all functions $f : \mathbb{R} \to \mathbb{R}$ such that
$$
f(xf(y) - f(x)) = 2f(x) + xy
$$
for all real numbers $x, y$.
$$
f(xf(y) - f(x)) = 2f(x) + xy
$$
for all real numbers $x, y$.
MathNet 2017-part-07 — 172 problems (EN–VI) Question 171
Math Olympiad Vault · MathNet 2017-part-07 — 172 problems (EN–VI)