true or false

9. Cu In a maximization integer programming problem, any feasible integer solution becomes an upper bound in one iteration of the branch and bound algorithm. 10. [ ] In a minimization integer programming problem, when there exist multiple different integer feasible solutions, the one with the largest objective value should be chosen as a better upper bound. 11. [ ] Heuristic algorithms are usually more computationally efficient than analytic algorithms. 12. [ ] Simplex method can be directly applied to solve integer programming problems