Ok, the question I'm having trouble with is attached as an image in this post. I can re-arrange for "w", but that's about it.

Any help would be appreciated.

EDIT - It's just occurred to me that the equation makes no sense without knowing the context, so I've uploaded the whole question, but it's just part b) that I'm having trouble with. I don't want the whole answer, I just simply need a little push toward it.

EDIT 2 - I've more or less solved it now, so no need to keep the question up.