Example of use of Slack and Surplus Variables
6 X1 + 3X2 £ 10 (1)
3 X1 + X2 = 7 (2)
7 X1 + 4X2 + X3 ³ 10 (3)
FSince (1) and (3) are inequalities we need to add a slack (1) and subtract a surplus variable (3) accordingly. Then the inequalities can be expressed as equations of the form:
6 X1 + 3X2 + S1 = 10 (1)
3 X1 + X2 = 7 (2)
7 X1 + 4X2 + X3 S3 =10 (3),
Where S1 is a slack variable and S3 is a surplus variable. What is the physical meaning of these variables?