Cho X ( Z ) = 1 ( Z − 1 ) 2 với | Z | > 1 , thì:

$x\left(n\right)=\left(n+1\right)u\left(n-2\right)$

$x\left(n\right)=\left(n-1\right)u\left(n+2\right)$

$x\left(n\right)=\left(n-1\right)u\left(n-2\right)$

$x\left(n\right)=\left(n-2\right)u\left(n-2\right)$