6

Part of 1989 Federal Competition For Advanced Students, P2

Problems(1)

Source: Austria 1989

Determine all functions

f: \mathbb{N}_0 \rightarrow \mathbb{N}_0

such that f(f(n))\plus{}f(n)\equal{}2n\plus{}6 for all

n \in \mathbb{N}_0

functionalgebrapolynomialalgebra unsolved