Find the critical points for the function $$f(x,y) = x^{3}+y^{3}-9x^{2}-3y-7$$ and classify each as a local maximum, local minimum, saddle point, or none of these.

critical points:
(give your points as a comma separated list of (x,y) coordinates.)

classifications:
(give your answers in a comma separated list, specifying maximum, minimum, saddle point, or none for each, in the same order as you entered your critical points)