uzziah4200 uzziah4200 30-11-2022 Business contestada Find the extreme value(s) of each of the following functions and determine whether they are maxima or minima: [10] a) z = x2 + xy + 2y2 + 3 [10] b)2=-x2-y2 + 6x + 2y [10]c) z = 3x3-5y2-225x + 70y + 23 Zー