In the dual simplex method dual feasibility (primal is a maximization problem) is maintained by:
a.at least 1 variable in row 0 is negative.
b.row zero is nonnegative.
c.at least 1 right-hand side is negative.
d.each right-hand side is nonnegative.
Question 2
If the ith dual variable is positive then:
a.ith primal variable = 0.
b.ith primal slack = 0.
c.ith primal variable is nonbasic.
d.ith dual slack = 0.