9-12. Assume the second derivatives of f are continuous throughout the xy-plane and fx (0, 0) = fy (0, 0) = 0. Use the given information and the Second Derivative Test to determine whether f has a local minimum, a local maximum, or a saddle point at (0, 0), or state that the test is inconclusive. 9. fxx (0, 0) = 5, fvy (0, 0) = 3, and fry (0, 0) = -4 10. fxx (0, 0) = -6, fyy (0, 0) = -3, and fry (0, 0) = 4 11. fxx (0, 0) = 8, fyy (0, 0) = 5, and fry (0, 0) = -6 12. fxx (0, 0) = -9, fyy (0, 0) = -4, and fry (0, 0) = -6