I can display linear equations within the graph using
$a = random(3,9,1);
$ftex = "$a$x+1";
And then within the graph, provide:
$label4= new Label(3.2 , 2 , $ftex,'black',('center','center'));
$graph1 -> lb($label4);
But can not figure out how to get a formatted LaTeX expression to appear (specifically one involving symbols or letters such as \theta).