2. The following is the current simplex tableau of a linear programming problem. The objective is to minimize -2x4-x5 - 2x6, and x1, x2, and x3 are the slack variables. Row Z X1 X2 X3 X4 Xs X6 RHS 0 Z 1 b C 0 0 h g -42 1 X6 0 6 0 -14 0 1 1 a 2 X2 0 6 d 4 0 5 0 10 3 X4 0 0 e f 1 2 0 0 (a) Find the values of the unknowns a through h in the tableau. (b) Find B-1. (c) Is the tableau optimal?