Oh, that's a very different question from what I was answering. However, I can tell you right off the bat that if you have more than about 5 irregular zeros, you're not going to be able to compute one of the equations very quickly. I'd recommend that you read up on
Interpolation and especially
Polynomial Interpolation to figure out the equation. It depends on how irregular your data points truly are, but your function will probably have a degree on the order of N-1, where N is the number of data points.