Question 159
Determine all pairs of polynomials $(P, Q)$ with real coefficients satisfying
$$
P(x+Q(y))=Q(x+P(y))
$$
for all real numbers $x$ and $y$.
$$
P(x+Q(y))=Q(x+P(y))
$$
for all real numbers $x$ and $y$.
MathNet 2017-part-03 — 176 problems (EN–VI) Question 159
Math Olympiad Vault · MathNet 2017-part-03 — 176 problems (EN–VI)