Develop the B&B tree for each of the following problems. For convenience, always select x, as the branching variable al node 0. *(a) Maximize z 3x₁ + 2x. subject to 2x + 5x 18 4x + 2xy = 18 X₁, Xy0 and integer 7x + 5x 36 4x₁ + 9xy = 35 X₁, Xy a 0 and integer 2xy + 5xy 27 6x + 5x₂ = 16 X₁, Xy 20 and integer 3x + 2x₂ in 5 2xy + 3xy a7 XyXy in 0 and integer 5x₁ + 9xy 41 X. Xy0 and integer (b) Maximize 2 - 2x + 3xy subject to (c) Maximize 2 - 2x + 2xy subject to (d) Minimize z-5x, + 4xy subject to (e) Maximize z 5x₁ + 7xy subject to