Determine the z-transforms of the following finite-duration signals. (1) x1(k)={1,2,5,7,0,1} (2) x2(k)={1,2,5,7,0,1} (3) x3(k)={0,0,1,2,5,7,0,1} (4) x4(k)={2,4,5,7,0,1} (5) x5(k)=(k) (6) x6(k)=(km),m>0