[JaredL]

It's correct. It's more intuitive to rewrite it:

Your formula:
EV = -(B -(B * FE)) + (P * FE)

Rewrite:
EV = P*FE - B(1-FE)

The first term is the probability that she will fold, times the amount you win if she does. The second term is the probability that she will call (call probability = 1 - fold probability) times the amount you lose if she does. The second term could also be interpreted as the sum of the call probability and the raise probability if you won't be calling a raise.

edited to add:

When calculating expectations of anything, you always take the probability of each possible event and multiply it by the corresponding amount should that event take place. Then you add all of these up to get the expectation.

So here there are two events, that she folds and that she doesn't (again, I'm assuming either you or her are all-in or that you will fold to any raise). She folds with probability FE using your notation. That means she calls/raises with probaibility 1-FE. If she folds you win P, if she calls or raises you lose B. So to find your expected value for this play, add P*FE and -B*(1-FE) as you did.