Let fx y (x, y) be constant on the region where x and y are nonnegative and x + y s 30. Find f(x ly) a f(xly) = 1/(30-y), OS X, O Sy, x + y s 30 b.fy(y) = (30-4)/450, Osy s 30 fxl y) = 450/(30-y), O Sx, 0 sy, x + y s 30 d. f(x ly) = 1/450, OS X, O Sy, x+y = 30