Find the critical point(s) and determine whether each is a local maximum, local minimum, a saddle point, or none of these. f (x, y) = 350 – 3x2 – 4x + 2xy – 9y2 + 887 Enter the critical point(s) as point(s) (a, b) in increasing order of the x-coordinate. If there are less than three critical points, enter the critical points first and then select "none of these" and enter NA in the remaining answer field(s). f has a local maximum v at (2,8) f has none of these at NA s has none of these none of these INA NA