1. (20 points) Solve the following problems using: i.graphical method ii.Solver from MS Excel iii. AMPL max Z s.t.: C1 З х1 + 4 x2 <= 120 C2—4x, + 2х,

> 10 C3 x1 + x2 <= 35 С4 4 х1 + 4 x2 >= 50 x1, x2 >= 0 a) Z = x1 + x2 b) Z = 2 x1 +5 х2 c) Z = 3 x1 + 4 x2 d) Z = -2x1 + x2