num=[2 1.4 -0.9 -0.158 0.4104 0.0294 -0.0668]

den=[1]

figure(1)

zplane(num,den)

num1=[1 2.7 -12.61 -24.757 66.301 62.072 -126.786]

den1=[1]

figure(2)

zplane(num1,den1)

num2=[0.2 -0.26 1.934 10.413 1.934 -0.26 0.2]

den2=[1]

figure(3)

zplane(num2,den2)

num3=[1.25 0.5 -2.1 -2.1 0.5 1.25]

den3=[1]

figure(4)

zplane(num3,den3)

num4=[1.1 3.12 -2.5 0.6 0.5 0.006 1]

den4=[1]

figure(5)

zplane(num4,den4) -good