SHAIK AASIF AHAMED12 Years agoHello student,Please find the answer to your question belowGiven expression is1+5/4(z^-1)+5/4(z^-2)+(1/4z^-3)=1+(5/4z)+(5/4z2)+(1/4z3)by taking LCM we get=(4z3+5z2+5z+1)/4z3