Which of the following combinations of constraints has no feasible region? Assume nonnegativity constraints. a. x1 + x2>=15 and x1 - x2 =100 and x1

Which of the following combinations of constraints has no feasible region? Assume nonnegativity constraints. a. x1 + x2>=15 and x1 - x2<=10 b. x1 + x2<= 5 and x1>=10 c. x1 + x2>=100 and x1 + x2>=50 d. x1 + x2>=10 and x1>=5 e. All of the above have a feasible region.

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