clc;
close
clear;
z=%s;
b0=1;
b1=2;
b2=3;
a1=4;
a2=5;
tf=syslin('d',((b0+b1*z^-1+b2*z^-2)/(1+a1*z^-1+a2*z^-2)));
ss=tf2ss(tf);