plot1=Plot[{{120 - 2 q}, {60 - q}, {60-q/2}}, {q, 0, 120}]
plot2 = ListPlot[{{0, 60}, {30,30}, {40,40}, {60,0}},  PlotStyle -> PointSize[.02]] 
Show[plot2, plot1, PlotRange -> {{0, 130}, {0, 130}}, 
 AspectRatio -> 1/1]

 


plot3 = Graphics[Text["Firm 1's Reaction Curve", {80,30}]]
plot4= Graphics[Text["Firm 2's Reaction Curve", {30,80}]]
plot5 =  Graphics[Text["Cournot equilibrium", {42,42}]]
plot6 =  Graphics[Text["Cartel Output", {32,32}]]

Show[plot2, plot1,plot4, plot3,  plot5, plot6,  PlotRange -> {{0, 130}, {0, 130}}, 
 AspectRatio -> 1/1, AxesLabel->{"Firm 2's Output","Firm 1's Output" }]

 

http://reference.wolfram.com/legacy/teachersedition/MathematicaBook/31.2.html

http://www.physics.mun.ca/~cdeacon/laboratories/graphs/graphplot.pdf

 I coudl not get the Export command to work to go to a particular location. Instead, just right-click on the ojbect and save to a pdf file wherever you like

 

Labeled[expr, {lbl1, lbl2, ...}, {pos1, ...}]


Inseet does soemthing too.