a) Partially solve the IP model graphically (for t=1 and = 2, two sketches only) by using the Branch- and-Bound Method (Use a graph paper or other graphing sheet but be sure to implement a reasonable scale). Show the feasible region, and plot the objective function through the optimal point as a dashed line (---) for ench subproblem solution. Indicate the optimal values of the variables and objective function for each subproblem solution and indicate all additional constraints, as shown below. When you need to branch, branch on xz, first if there are two choices. Indicate all additional constraints from t-1 to create the subproblems and all additional constraints from t-2 to create the subproblems. Maximize Z = 2x: + 3x2 Subject to: 4x + 2x2 20 (CI) 2x+ 5x2 30 (C2) X2, X2 0, X, xa integer Fort-1, show the results: VIVIA Z- All constraints added to tal to create subproblems: Constraint added to t=1 to create t-2: For t=2, show the results: Z- All constraints added to t-2 to create subproblems: b) Write the IP model needed to solve the problem in LINDO with labeling its constraints. Use INT or GIN as an appropriate in LINDO