How to... equations and functions



Hello!

I'm new to maxima and was wondering how to do the following:

I have an equation e:x+3=2*x-2; and I'd like to create a function of it's 
right hand side: f(x):=rhs(e);

What do I have to type into maxima to get this working?

If I type f(x):=rhs(e); all seems fine, until I try to calculate a result for 
some x. f(2) doesn't return a result, but instead just says 2*x-2.. as if x 
was still unknown.

thanks,
Max