## Quick Reference

When slack variables have been introduced into a linear programming problem there are more equations than there are variables. If there are *n* more variables than equations the basic solutions are found by setting various combinations of *n* variables to zero, thus reducing the number of variables to the number of equations. If one of the slack variables is negative then that solution is not feasible. For each solution, the *n* variables set to zero are called non-basic variables and the others are called basic variables.

*Subjects:*
Mathematics.