How do you solve the difference equations?

How do you solve difference equations?

The forced response of a DLIT system can be done by iteratively solving a difference equation of order n, or by the discrete convolution of the input with the impulse response of the system. […]

FIR digital filters

The output of an FIR filter at a certain moment is given by the linear combination of the input samples taken in a finite number of previous moments. […]