P-9.4 An LTI system is described by the difference equation = y[n] 0.1 (x[n] x[n-1]+x[n-2]) (a) Determine the system function H(z) for this system. (b) Plot the poles and zeros of H(z) in the z-plane. (c) From H(z) obtain an expression for H (el), the frequency response of this system.