5. A linear programming model is given as follows:

Minimize = 81 + 62

Subject to 41 + 22 20

61 + 42 12

1 + 2 6

1, 2 0

a. Define the feasible solution area and obtain the optimal solution graphically (26th question in the book).

b. If the coefficient of 2 in the objective function decreases to 4, what effect will be?

c. If the second constraint, 61 + 42 12, is removed from the given model, what effect will be?

d. If a new constraint, 41 + 62 24, is added to the given model, what effect will be?