solution

>	plot([x^2,4*x-4],x=-1..3,y=-2..10,color=[blue,black],thickness=[3,0],linestyle=[1,3]);

>

----------------------------------------------------------------------------------------------------------

>	with(plots): a:=plot(x^2,x=-1..3,y=-2..10,color=blue,thickness=3,linestyle=1): b:=plot(4*x-4,x=-1..3,y=-2..10,color=black,thickness=0,linestyle=3): display(a,b);

>