please help me

3. An LTI system is shown below consisting of two cascaded sub-systems systems, #1, and #2, respectively Xin] LTT #1 hi LTI # 1 Ha Yraz The following specifications are given: Impulse response, he[n] = 28 In-1) - 25 in-2) and Hz (Z) = Z1-Z")/(1-z-) (a) Find the impulse response of h (n) of the overall system #1 and #2 (b) Determine the output y[n) if x[n] = 3 + 2 cos ((1/2)n) + 2 cos ( ntn - 1/2)