f ( x, y) = 2xy - 2x2 - 31 + 8x+ 8y-6 Local maxima are Local minima are Saddle points are f(x, y) = 6xy - 4x2 +8x - 7y+4 Local maxima are Local minima are Saddle points are f (x, y ) = x2 - 7xy+ y + 4y+8 Local maxima are Local minima are Saddle points are