b$)$ Use the residuez$()$ function in MATLAB to perform the partial fraction expansion of $($hint: your

result should contain one repeated root$)$: $\frac{8\mathrm{.}5-15z^{-1}}{1-10z^{-1}+25z^{-2}}.($Hand in the final solution only$-$

no MATLAB code.$)$

c$)$ Use the residuez$()$ function in MATLAB to perform the partial fraction expansion of $($hint: your

result should contain an improper portion$)$: $\frac{1-6z^{-1}+12z^{-2}}{1-4z^{-1}+3z^{-2}}.($Hand in the final solution only$-$

no MATLAB code.$)$