Could you please edit your first post then ? And eventually put it in LaTeX.

Hmm, this is not what I would call recursion. However, what I mean is that it may not even be possible to isolate all N terms on one side, you might fall into a situation where trying to move one N term on a side will make the other go on the other side. And algebra is useless in this situation. So either you :

- try to see what can be done with very, very advanced mathematics (believe me, five variables, you are going to have a lot of fun)

- need to put up with it and try to find a solution (you are gonna have fun too ...)

Here, I put it in LaTeX for you, is that right ?

(my eyes !)

Maybe someone will be courageous enough to give it a shot, I would've helped you but I can't stay anymore now :(