Do you mean you want to solve that equation for h? (That's a different thing than "evaluating it", which would not be possible since the left hand side is not the sort of expression to which you can assign a value -- and what does is to assign a value. Whereas == denotes an equality.)
Perhaps you mean something like the following:
Solve[A Log[h]/h - x == 0, h]
The result you'll get gives the solution as:
h -> -((A*ProductLog[-(x/A)])/x
This may or may not be of use to you, since ProductLog is a not an "elementary" function.
Do A and x have some specific values?
By the way, it's a bad idea to use names in Mathematica that are, or begin with, an upper-case letter -- because that risks confounding them with the names of built-in objects.
On Sep 23, 2013, at 9:59 PM, Dhaneshwar Mishra <firstname.lastname@example.org> wrote:
> > I would like to evaluate A*Log[h]/h -x=0 for h, can any body help me doing so? > > I am beginner for Mathematica.
--- Murray Eisenberg email@example.com Mathematics & Statistics Dept. Lederle Graduate Research Tower University of Massachusetts 710 North Pleasant Street Amherst, MA 01003-9305