delta epsilon proof for limit of multivariable function

lim x^2 / (x+y)

(x,y) ~> (1,2)

I find that the limit is just 1/3. but i don't know how to prove this using the delta epsilon definition. i have that |x^2 / (x+y) - (1/3)| < epsilon and sqrt((x-1)^2 + (y-2)^2) < delta. i have fiddled with the inequalities for a while but it doesn't seem to be getting anywhere. i am trying to see if i can find a relationship between epsilon and delta but am having trouble doing so. can anyone provide me a some hints in the correct direction? thanks