Let f(x, y) = 3y^2 2xy + 12x.

a) Find the first and second partial derivatives: fx, fy, fxx, fxy, fyx, fyy.

b) Find the critical point(s).

c) Calculate the value D = fxx fyy (fxy)

2 at each critical point, and determine if the critical point is a local minimum, local maximum, saddle point, or neither. (D > 0 and fxx > 0 is local min; D > 0 and fxx < 0 is local min;

D < 0 is a saddle point)