z .6 ------+ ------= 1 z-4 .z
Z^2 6z-24 z^2-4z -------- + --------- = --------- z(z-4) z(z-4) z(z-4) z^2+6z-24-z^2+4z=0 10z-24=0 10z=24 z=2,4