Consider the following linear programming problem. 4A + 5B Min s.t. 1A + 4B 0 A,B20 (a) Find the optimal solution using the graphical solution procedure and the value of the objective function. at (A, B) = (b) Determine the amount of slack or surplus for each constraint. slack for 1A + 4B = 21 surplus for 2A + 1B 27 slack for 3A + 1.5B 0 1 (c) Suppose the objective function is changed to max 7A + 3B. Find the optimal solution and the value of the objective function. - at (A, B) = ([