ff = [-100 -150 -200 -400];  % vector to define the objective function
 aa = [10 12 25 20; 2 4 8 12; -1 0 0 0; 0 -1 0 0; 0 0 -1 0; 0 0 0 -1]; % matrix to define constraints
                                                                       % (left hand side)
bb = [500 150 0 0 0 0];    % matrix to define right hand side of constraints
[x,fval,exv,out,lam] = linprog(ff,aa,bb)
%
% to see the Lagrange multipliers, look at the vectors lam.ineqlin or lam.eq
% look at matlab online help: "help linprog" for more details
%