linear programming
posted by nmh .
Minimize z = 3x + 6y subject to:
4x + y ≥ 20
x + y ≤ 20
x + y ≥ 10
x ≥ 0
y ≥ 0
Graph the feasibility region.
Identify all applicable corner points of the feasibility region.
Find the point(s) (x,y) that minimizes the objective function z = 3x + 6y.

I am having trouble with this one as well. please help!