(8) (9pts) Use the Second derivative test on the f(x,y) = x2 - xy + 2 + 2x + 2y -4 to find and classify all local minima, local maxima and saddle points. Find the function value at these points. (9) (9pts) Use Lagrange multipliers to find the extreme values of f(x, y) = x3 +y on a2 + y? = 1