Find the local extrema of the following function f x y 9x 4xy 4y 198x 108y 3 Find f x y and f x y f x y 18x 4y 198 fy x y 4x 8y 108 Identify the location of any local maxima Select the correct choice below and if necessary fill in the answer box to complete your ch A There are local maxima located at Type an ordered pair Use a comma to separate answers as needed B There are no local maxima