Consider the following problem:

Minimize

Subject to:

x_1, x_2, and x_3 ? 0.

a) Reformulate this problem to fit the standard form for a linear programming model. (Be clear)

b) Using the Big M method, work through the simplex method step by step to solve the problem.

c) Using the two phase method, work through the simplex method step by step to solve the problem.

d) Using both R package and Excel solver Ad-in based on simplex method to solve the problem.

2 = 2.1 + 3.2 + Tz