{ Exmpl3.3-5_Unbounded.mpl }
{ Winston, Operations Research, Applications and Algorithms, 4th ed. }
{ Chapter 3.3, Example 5, Product-Mix, Size: 2x2, Page 66 }
MAX z = 2 x1 - x2;
SUBJECT TO
x1 - x2 <= 1;
2x1 + x2 >= 6;
END