MathDB
f (xf (y) - yf (x)) = f (xy) - xy

Source: 2020 Grand Duchy of Lithuania, Mathematical Contest p1 (Baltic Way TST)

October 3, 2020
algebrafunctionalfunctional equation

Problem Statement

Find all functions f:RRf: R \to R, such that equality f(xf(y)yf(x))=f(xy)xyf (xf (y) - yf (x)) = f (xy) - xy holds for all x,yRx, y \in R.