Need your help to answer all questions number 1-5. Please don't answer only one number but all questions? thanks

Watch-me Example 1: For z = f(x, y) = x2 + 2y2 - 4xy+ 2x + 4y + 5, find all relative extrema. Watch-me Example 2: For z = f(x, y) = x3 + y3 - 3y2 - 3x + 9, find all relative extrema. Watch-me Example 3: Fly Straight, Inc. produces two kinds of golf balls, one kind that sells for $3 and one that sells for $2. The total Revenue, in thousands of dollars, from the sale of x thousand balls at $3 each and y thousands at $2 each is given by R(x, y) = 3x + 2y The company determines that the total cost, in thousands of dollars, of producing x thousands of the $3 ball and y thousands of the $2 ball is given by C(x, y) = 2x2 - 2xy + y2 - 9x + 6y+7. How many balls of each type must be produced and sold to maximize profit? Watch-me Example 4: A company sells two models of cellular phones: the basic model and the luxury model. The demand functions for the cellular phones sold are given by Pb = 160 - 0.15x - 0.05y and p = 220 - 0.15x - 0.15y, where po and pr are the prices of the two models in dollars, x is the units of the basic cellular phones sold per week, and y is the units of the luxury cellular phones sold per week. Therefore, the total weekly revenue function R(x, y) is R(x, y) = 160x + 220y - 0.2xy - 0.15x2 - 0.15y?. Determine how many units of each model should be sold per week in order to maximize the company's total weekly revenue. example 5: Suppose that you are given the following information: fxx (x, y) = 2xy; fry (x, y) = fyx(x, y) = 3x2; fyy (x, y) = by and there are 2 critical values (1, 1); (-1,1). Use the D-test to determine if those two critical values are relative maximum, relative minimum, or saddle point