In a signal x(n), replacing the independent variable ‘n’ by’-n’ results in x(-n). The result of this operation is a folding or a reflection of the signal about the time origin n=0.
A signal x(n) may be shifted in time by replacing the independent variable ‘n’ by ‘n-k’, where k is an integer. If ‘k’ is a positive integer, the time shift results in a delay of the signal by k units in time.
x(n)= {2,1,3,4,2} & x(-n)= {2,4,3,1,2} & x(n-2)={2,1,3,4,2} � �