IN-TST 2001 Problem 8

Find all functions $f \colon \mathbb{R_{+}}\to \mathbb{R_{+}}$ satisfying : $f ( f (x)-x) = 2x$ for all $x > 0$ .

Dataset text AI-MO AoPS. Quoted with source.

Solutions

No solution is on olymmath yet. Official and human solutions come first when they arrive. AI solutions come after them, with a label.