AS2: Split a string

Hi, can somebody help with this, just cant get a solution to the problem

I have an input box where users are entering they answer to a randomly generating algebra equations, I need to be able to break the string apart that they enter so that I can check their answer is correct

so 2x+3y-5 needs to be broken apart to 2x, 3y, -5

-5x-2y+7 needs to be -5x, -2y, +7

I just cant get it to split apart and remember what the +/- delimiters are, can anyone help me out??