2. Solve these problems using graphical linear programming and then answer the questions that follow. Use simultaneous equations to determine the optimal values of the decision variables. Minimize Z=1.80S+2.20T Subject to: Potassium 5S+8T200gr a. Carbohydrate 15S+6T240gr Protein 4S+12T180gr TT10gr S,T0 Minimize Z=2x1+3x2 Subject to: b. 4x1+2x22x1+6x21x1+2x2x1,x22018120 (1) What are the optimal values of the decision variables and Z ? (2) Do any constraints have (nonzero) slack? If yes, which one(s) and how much slack does each have? (3) Do any constraints have (nonzero) surplus? If yes, which one(s) and how much surplus does each have? (4) Are any constraints redundant? If yes, which one(s)? Explain briefly