3. (15 pts.) Partial Fraction Expansion (PFE): (a) For the transfer functions below please answer the following questions: i. what are the zeros z and the poles pi ii. what is the multiplicity mi of each pole pi? iii. is the system stable? (b) Using the PFE write the transfer functions below as sum of terms in the form Np_1 mail EXPW 2:0 3:0 where Ti]- is the residue relative to pole pi with multiplicity m1 > Land N10 is the number of distinct poles. . _ ,2 1' H1(Z) _ ligzl+%z2 471 '1 3 332(3) = _3 iii. (Extra credit: 5pts.);H'3(z)=1