Solve the following LPs using the simplex method. Comment on whether the optimal objective function value is bounded or unbounded. If the optimal objective function value is unbounded, then find a direction of unbound- edness. If the optimal objective function value is bounded, then comment on whether the optimal solution is unique or there are multiple optimal solutions. (a) @ (d) max 2x + x x.t. -21+2252 -21 +254 21.22 20 max 2r + 3xy s.t. 21-2 2 -271+ 3 1.220. max 5r1 +4 s.t. 21 + $12 21 +47 512 -271+51 3251 $1,42 20 max 24r +60ry-3-674 st. +37-55 2r+62-22 10 11.12.20 max 5x +5x s.t. 21 + 6 -3+420 $1.3220