1-a) Use the Lagrange multiplier to find the maximum value of f (x, y) = 4xy subject to the constraint, x + 2y = 40. 1-b) Also state the associated values of x, y, and 1. 2-a) Find the maximum value of Q = 10 (KL) subject to the cost constraint, K + 4L = 16. 2-b) Estimate the change in the optimal value of Q if the cost constraint is changed to K + 4L = 17