linprog - Solve linear programming problems

Finds the minimum of a problem specified by

f' x such that A x <= b, Aeg = Beq, lb <= ub

where f, x, b, beq, lb, and ub are vectors, and A and Aeq are matrices.
Find x that minimizes 

f(x) = –5x1 – 4x2 –6x3,

subject to

x1 – x2 + x3 ≤ 20
3x1 + 2x2 + 4x3 ≤ 42
3x1 + 2x2 ≤ 30
0 ≤ x1, 0 ≤ x2, 0 ≤ x3.

First, enter the coefficients

f = [-5; -4; -6];
A =  [1 -1  1
      3  2  4
      3  2  0];
b = [20; 42; 30];
lb = zeros(3,1);
Next, call a linear programming routine.

[x,fval,exitflag,output,lambda] = linprog(f,A,b,[],[],lb);

linprog