This post could have been about me when I was her age, only with me the problem was in Geometry.

I'm also one who's *really* hard on myself if I get anything but an A, so I understand where she's coming from.
Encourage her to hang in there and not to consider herself a failure over one low grade. Also not to give up because of one low grade, either.
In the meantime, see if you can find some extra practice things she can use. Flash cards, games (I loved games), tutor... anything to get more practice, because this stuff comes only with practice. You may also try other textbooks, because each textbook has slightly different ways of presenting the material, and one may present it in a way that makes more sense to her than her current book or teacher.
Also, something I found very, very, VERY helpful when I was having trouble in any math class (still do for that matter) was a dry erase board (one of those that's about 2.5 feet by 3 feet). Being able to work out the problem on a larger board than a piece of paper and on something that made it easy to erase and try again really helped, strange as that may sound. To this day, when I'm having difficulty with a problem at work or in school (since I'm going for my Master's), I find it much easier to solve if I can work it out on a dry erase board. If you don't have something like that, I highly recommend it.
And, encourage her to *never* skip any steps. Getting a good foundation in Algebra is very important, and if she starts skipping steps in problems (like I always wanted to do), that's going to open up room for mistakes, if not in this class then in future classes (I had to learn this the hard way

). What I mean is like this:
Say you have the following:
x - 2 = 0
Instead of just writing
x = 2
Write every step:
x - 2 = 0
x - 2 + 2 = 0 + 2
x = 2
On such a simple example, it really seems to waste time and space, but if she gets into that habit *now*, it'll really, really help in future classes. I was one who kept wanting to go straight to x=2 from x-2 = 0.
Good luck!! And assure her that even if she's having a problem in one aspect of the math now, if she keeps at it and doesn't give up, it'll come to her.

She's a smart kid.

It may take a while for it to click, but it *will* eventually click if she keeps at it.
