I want a solution to this question

(a) Find fi(x,y), fy(x,y), f.(1,3), and fy(-2,4) for the given function. If z = f(x,y) = 3x3y2 - x2y3 + 4x +9 (b) A firm estimates that it can sell Q units of its product with an advertising expenditure of x thousand dollars where Q = Q(x) = -x2 + 600x + 25 i) Over what level of advertising expenditure is the number of units of product sold increasing? ii) Over what level of advertising expenditure is the number of units of product sold decreasing? c) Determine the location and values of the absolute maximum and absolute minimum for the given function: f (x) = (-x+2)+, where Osx