15. Let ( - w) + dix1 + d2x2 + . . . + dmxm= 0 (* ) be the phase I objective function when phase I terminates for maximizing w. Discuss the following two procedures for making the phase I to II transition when an artificial variable remains in the basis at value zero. Show, using either procedure, that every basic solution determined during phase II will be feasible for the original problem formulation. a) Multiply each coefficient in (*) by -1. Initiate phase II with the original objective function, but maintain (*) in the tableau as a new constraint with (w) as the basic variable. b) Eliminate (*) from the tableau and at the same time eliminate from the problem any variable x ; with dj