Maximize

z = - 3x_{1} + x_{2}

subject to

- x_{1} + 4x_{2} >= 4

10x_{1} + 5x_{2} >= 5

- x_{1} + x_{2} <= 4


x_{2} >= 0

Let the surplus of constraint (1) and (2) be x3 and x4, respectively, and the slack of constraint (3) be xs. Answer the following independent questions:​