DT LTI System
$ \ y[n] = 2x[n + 3] + x[n - 8] $
Unit Impulse Response:
$ \ h[n] = 2 \delta[n + 3] + \delta[n - 8] $
Frequency Response:
$ \ H(s) = \sum_{- \infty}^{\infty}h[n]e^{j \omega n} $
Plugging in the values:
$ \ H(s) = \sum_{- \infty}^{\infty}(2 \delta[n + 3] + \delta[n - 8])(e^{j \omega n}) $
$ \ = 2e^{j \omega 3} + e^{-j \omega 8} $
