Answer:

xy = 2009(x-y)= 7×7×4 1/2009 = 1/y，

Let the greatest common divisor of X and Y be K, and let x=Km, y=Kn, M and N be coprime, then XY = 2009 (X-Y) = 7× 7× 4/kloc-0 /× (X-Y) becomes KMN = 7× 7× 4/kloc-0 /× (.