Simplex method in prime how to use the constrains maximise s.t. constraints.

[Anthony The Koala]

I found a reference to the Simplex method. But it does not specify how to specify maximise subject to constraints then plotting.

Reference: "HP prime guide finite mathematics" ISBN 9780195573035, page 61.

Minimise: C = 6x + 5y
Subject to:
x >= 0, y >= 0
2x + 4y >= 22
3x + 2y >= 20
4x + 5y >= 40

I tried using the Advanced Graphics app.
When I entered x>= 0 into the editor, I got a syntax error.

Is there a way of entering the equations into the Advanced Graphics editor then to plot using Plot and see the various graphs of the equation when pressing Plot?

Thank you
Anthony, Sydney