This may be a dumb question, but I often need to solve expressions for something other than a variable. As a trivial example, say we have a common-emitter amplifier:

Vout = Vsupply - (Vin - Vbe)((hfe + 1)/hfe) * RC/RE

And I want to solve it for the DC transfer function Vout/Vin. Can Mathematica do this, at all?

Now, I understand there is actually no solution here, but a small change makes it solvable (and still easy to reason around):

Vout = - (Vin - Vbe)((hfe + 1)/hfe)*RC/RE

Now, this simple example I can solve easily. But there are complex expression created in cascades of stages and ladders that get a bit more complex in hurry... But even being to solve the simple problems would be nice as a "calculator" function. I can calculate square roots and look up logarithms in tables myself also, but I sure prefer to work with a calculator.

Any ideas? Maybe I just missed something obvious?