I need to isolate the A.

Here's the equation:
D = P - FA

The answer is:
A = P - D
_____F

Here's what I did:
D = P - FA

D -P = -FA

D - P = A
_-F

I don't know if I did it wrong, or if I'm supposed to somehow switch the D and P, and make the F a positive. . . I'm confused.

Any help is greatly appreciate.
This probably seems like an odd topic :P
Thanks.