Hãy tìm x ( n ) biết. X ( Z ) = Z − a Z 2

$x\left(n\right)=\delta \left(n-1\right)-a\cdot \delta \left(n-2\right)$

$x\left(n\right)=a{}^n\cdot u\left(n-2\right)$

$x\left(n\right)=\delta \left(n-1\right)-a{}^n.u\left(n\right)$

$x\left(n\right)=\delta \left(n-2\right)\cdot a{}^n\cdot u\left(n\right)$