#4) f(x)=(x^2+x-12)/(x^2-x-6)
#4) make a complete sketch of f(x) labeling all intercepts and asymptotes.
p1=plot(f(x),-10,-2,color='red')
p2=plot(f(x),-2,3,color='green')
p3=plot(f(x),3,10,color='purple')
p4=plot(1,-10,10)
(p1+p2+p3+p4).show(ymin=-5,ymax=5)