MATLAB: I have a question

plot

I have a program where I assumed a Pressure (P(L)) to get at the end I have converge my pressure (P(L)) to get a real pressure by trial and error . now I need to plot it for various values of pressure , but I don't I am able to save my New (P(L)) to plot it verses T(Temperature) . If I can , can anyone give me a quick tip or example. cheers
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