Solving linear programming problems using the graphical method

Question

Hi.

I'm having a problem with graphical method in linear programming problems.

Image example

I don't know how draw the straight line Z=0, Z=6....

Answer 1

Well, I think I found an answer for my question.

Z=k

we will give values to k.

k=0, then 3x1 + 2x2 = 0 points (0,0) and x1= (-2/3)x2 -> (-2/3, 1)

and we can draw the straight line Z=0. Now, only we draw paralels line to Z=0 to find the optimal solution