Simulate the two linear time invariant systems using recursive and non$-$recursive $($FIR$)$

difference equations. $($ Assume causal system y$(-$n$)$ where n is positive is $0)$

$($a$)$ y$($n$)=$ y$($n$-1)+1/$k$($ x$($n$)-$x$($n$-$k$)]$

$($b$)$ y$($n$)=1/$k$($ x$($n$)+$ x$($n$-1)+...+$ x$($n$-($k$-1))]$

use n $=-10$:$39,$ k$=5$