.slack may be the values of the slack variables, or even the differences in between the values in the remaining and correct sides of your constraints. The initial slack is 0, which implies the values on the remaining and proper sides in the manpower (initially) constraint are exactly the same. https://paysomeonetodolinearprogr90421.aioblogs.com/82316945/linear-programming-assignment-help-things-to-know-before-you-buy