IS THIS SYSTEM TIME INVARIANT?
$ X_k[n] = d[n-k] \Rightarrow Y_k[n]=(k+1)2 d[n-(k+1)] $
TEST
$ d[n-k] \Rightarrow (k+1)2 d[n-(k+1)] \rightarrow [time delay] \rightarrow (k+1)^2 d[n -(k+1) - t_o] $
$ d[n-k] \rightarrow [time delay] \rightarrow d[(n-k) - t_o] \Rightarrow (k+1)^2 d[n -(k+1) - t_o] $
