Question

Find all surjective functions f:ℝ→ℝ such that for every x,y∈ℝ

f(x+f(x)+2f(y))=f(2x)+f(2y)

This is like... a third repost. The last few drowned. Hah.

Answer 1

there is a website call www.askdrmath.com
There are a lot of math professors that help with proofs on that site.
They also, archive the questions.

Answer 2

Thanks!