The LP relationships that follow were formulated by Jeffrey Rummel at the Connecticut Chemical Company. Which ones are invalid for use in a linear programming problem, and why?
Maximize = 6X1 + 1/2X1 X2 + 5X3
Subject to: 4X1X2+4 2X3 =70
7.9X1+4X2 =15.6
3X1, + 3X2 +3X3 =21
I9X2-1/3X3 = 17
-X1 - X2 + 4X3 = 5
4X1, + 2X2 +4 3vX3 =80