I have some difficulties with next problem:

Let f, F functions which are define on open interval I, and let a,b in R so that a!=0.
WE define: h(X) ax+b and also functions g, G on J=h^-1 (I) with
G(x)=(1/a)*F(ax+b), g(x)=f(ax+b).
Prove that if F'=f on I, then G'=g on J.

Thank you!