Linprog of max LP

For

Runing the code:

% Linprog defined on min problem and Ax<=b for max problem take - objectiveFunction
%% The problem
objectiveFunction = -1 * [10 6 -8];
A = [5 -2 6; 10 4 -6];
b = [20 ;30];
%%Sloution 
linprog (objectiveFunction, A,b)

I get that "Problem is unbounded." but the answer seems to be 170/3

[Torsten]

You forgot to include the condition x1,x2,x3 >= 0 in your problem formulation.

[Harel Harel Shattenstein]

Where should I add them? in the matrix A?

[Torsten]

lb = [0 0 0];
ub = [Inf Inf Inf];