Hello all. I was working through an example in my Physics book and am having trouble with the simplifying algebra (very rusty). I'll go ahead and skip forward to the step that's giving me trouble:

E = q/(4πεz^2) [ 1/(1-(d/2z))^2 - 1/(1+(d/2z))^2 ]

Sorry that's so hard to read on here. I basically need to find a common denominator and multiply everything through. It should eventually reduce to:

E = (1/2πε) qd/z^3

Thanks for your help!