What is Z transform?what is the need of Z transform in signal processing?

to represent a digital signal in frequency domain ,we are using z trans form

From its name , it ll transform a time domain digital signal (which is discrete in time & in amplitude)

in to its frequency domain form

not necessarily we find the transform of time domain digital signal .....we find of discrete signal .....which can be unilateral, bilateral...depending upon the limits of operation

evaluate utilising partial enlargement z/( z-a million)^3 = a million/(z-a million)^2 + a million /(z-a million)^3 then seek advice from z remodel pairs. i've got not got the reference pair available however the consequence is f(n) = a million/2 n^2 -- (a million/2)n