My son just asked me for help with a differentiation question (it's not a sneaky homework question, just part of his revision for forthcoming exams). It's been 20+ years since I did calculus so I had to give up.

Basically the question is to find dy/dx in terms of x and y for the equation:

y^2 + y = x^3 + 2x

I'm sure it's straightforward but just can't recall the technique to use. Some clues on how to solve it would be appreciated.