For each of the following difference equations determine the output response \(y[n]\) ?

(a) \(y[n]-4 y[n-1]=x[n]\) with \(y[-1]=2\) and \(x[n]=\left(\frac{1}{3}ight)^{n} u[n]\)
(b) \(y[n]+\frac{1}{3} y[n-1]=x[n]-\frac{1}{3} x[n-1]\) with \(y[-1]=1\) and \(x[n]=u[n]\)