For each value of A the function h(x, y) = x2 + y? X(2x + 6y 20) has a minimum value m(A). (a) Find m(A) m(A) = (Use the letterL for A in your expression.) (b) For which value of A is m(A) the largest, and what is that maximum value? maximum m(A) = (c) Find the minimum value of f (x, y) = x2 + y2 subject to the constraint 2x + 6y = 20 using the method of Lagrange multipliers and evaluate A. minimum f =