G1 = tf(0.9*[1 8/9],[1 .8]);
%step(G1);

c1 = conv([1 0.8],[1 0.8]);
c2 = conv(c1,[1 0.6 64.09]);
c3 = 0.9*[0 0 0 .9 .8];
c = c2 + c3;

CR = tf([0.9 .8],c);
step(CR);
title('Problem 7c: Step response of C/R, K=1');

% L0 = tf([0.9 0.8],conv(conv([1 0.8],[1 0.8]),[1 0.6 64.09]));
% rlocus(-L0);