Consider the following problem.

Maximize Z  5x1  x2  3x3  4x4, subject to x1 2x2  4x3  3x4 20 4x1  6x2  5x3 4x4 40 2x1 3x2  3x3  8x4 50 and x1  0, x2  0, x3  0, x4  0.

Work through the simplex method step by step to demonstrate that Z is unbounded.