Assume that the following specify a generalized linear programming problem:
Maximize:
f(x) = 2.x1 + 1.x2
Subject to
x1 + x2 $\leq$ 6
x1 $\geq$ 3
2x1 + x2 $\geq$ 4
x1 x2 $\geq$ 0
Graph this problem, identifying the three constraint equation lines and the feasible zone common to all of them. Plot dotted lines for values of 3, 6, 9 and 12 for the objective function f(x). What appears to be the highest feasible value of f(x), and for what values of x1 and x2 does it occur? Variables when using extrapolation of a time series concept?