I'm currently making the transition from single variable calculus to multivariable calculus, and the epsilon-delta proofs seem as daunting as ever. I'm currently stuck on this one: $$\lim\limits_{(x,y) \to (1,2)} \ x^2 +2y = 5$$
It seems really simple but I am not being able to find a relation between the epsilon and the delta. Can you help me?