Find the relative maximum and minimum values f(x.y) = 4x- 2y Select the correct choice below and, if necessary, fill in the answer boxes to complete your choice. O A. The function has a relative maximum value of f(x,y) = at (x,y) = (Simplify your answers. Type exact answers. Type an ordered pair in the second answer box.) O B. The function has no relative maximum value. Find the relative maximum and minimum values. f( x,y) = x +y-+ 18x-20y Select the correct choice below and, if necessary, fill in the answer boxes to complete your choice O A. The function has a relative maximum value of f(x,y) = at (x,y) = (Simplify your answers. Type exact answers. Type an ordered pair in the second answer box.) O B. The function has no relative maximum value