Hello. I've posted an imageshack link to this question because I haven't figured out how to enter in math fonts.

http://img193.imageshack.us/img193/6...question20.jpg
In this question q and d are constants representing charge and the distance between charges, but z is a variable. I've been trying to use partial fractions after simplifying the equation. I wound up with a constant multiplied by z/[(4z^2-d^2)^2], and using partial fractions I would up with z = (Az + B)(4z^2 - d^2) + Cz + E. Trying to solve for that has lead me nowhere though. Am I at least going in the right direction, or is there some other way to solve this that I'm entirely missing?

(I posted this in the math forum because, despite this coming from a physics text, it doesn't require any actual physics)