(9 points) Suppose f(x, y) = x + y - 8x - 2y + 2 (A) How many critical points does f have in R? (B) If there is a local minimum, what is the value of the discriminant D at that point? If there is none, type N. (C) If there is a local maximum, what is the value of the discriminant D at that point? If there is none, type N. (D) If there is a saddle point, what is the value of the discriminant D at that point? If there is none, type N. (E) What is the maximum value of on R? If there is none, type N. (F) What is the minimum value of f on R? If there is none, type N.