I am trying to figure out a way to solve for the unknowns in a given payment formula.

http://upload.wikimedia.org/math/c/c...ab8ad7347e.png

I would like to solve for i, P, and n. I don't know how to alter the formula to do this? Can someone help me?

With my basic math background I have tried to isolate the variables, but I keep doing something incorrect, because my solutions never prove correct.