Question 87
Find all functions $f: \mathbb{R}^2 \rightarrow \mathbb{R}$ that for all real numbers $x, y, z$ satisfies the equation
$$
f(f(x, z), f(z, y)) = f(x, y) + z.
$$
$$
f(f(x, z), f(z, y)) = f(x, y) + z.
$$
MathNet 2019-part-06 — 184 problems (EN–VI) Question 87
Math Olympiad Vault · MathNet 2019-part-06 — 184 problems (EN–VI)