Ok, I think it is not necessary, but I can add it:

The contribution margin is 1.2 monetary units/ units for a first product and 0.9 MU / units for the second product. What is the optimal production schedule for the following constraints when producing from A x ME and B y ME?

On the picture the restrictions (ie the straight lines) can be read off.

In Maxima you type in for example:

u(k,x1,y1):=-k*x+y<=-k*x1+y1;

load(simplex); u1:x>=0;

u2:y>=0;

u3:y<=5;

u4:u(-1/2,2,5);

u5:u(-3,6,3);

NB:[u1,u2,u3,u4,u5];

DB:1.2*x+0.9*y;

maximize_lp(DB,NB);

which solves the optimization problem (DB=9.9, y=3, x=6)

I hope this helps!

Ps: I don't want to know the answer of the optimal production schedule, because in stack the package "simplex" isn't currently supported. I only want to know how to color the area below the constraints