Hãy chuyển X ( Z ) về dạng phân thức tối giản. X ( Z ) = 4 Z ( Z + 1 ) ( Z 2 − 2 Z + 1 )

$\text{X}\left(\text{Z}\right)=\frac{2}{(Z-1){}^2}+\frac{1}{Z-1}+\frac{1}{Z+1}$

$\text{X}\left(\text{Z}\right)=\frac{1}{(Z-1){}^2}-\frac{1}{Z-1}-\frac{1}{Z+1}$

$X\left(Z\right)=\frac{2}{(Z-1){}^2}+\frac{1}{Z-1}-\frac{1}{Z+1}$

$X\left(Z\right)=\frac{1}{(Z-1){}^2}-\frac{2}{Z-1}-\frac{1}{Z+1}$