Using the DTFT method, find the zero-state response y[k] of the causal system with frequency response and input given below:
$H(\Omega) = \frac{e^{j\Omega} + 0.32}{(e^{j\Omega} + 0.2)(e^{j\Omega} + 0.8)}$ and the input $f[k] = (-0.4)^k u[k]$
(Hint: $\sum_{k=0}^{\infty} r^k = \frac{1}{1 - r}, \quad |r| < 1$)