Of course you should bother!!! There's always a way of solving problems, at least in part.

But the problem here is the follow: you want us to help you solve a problem which conditions seems to change at your will!!! =P
First you needed to find all unknowns, including the difference, and now we can just forget about that part and replace it with others operations...

Solve THIS part of the problem first before asking for any further help. What will be the practical outcomes of the results,and what exactly must you mathematically extract from the system?

I can't solve my own problems without knowing these, therefore others'... =P