The sequence is .

The first term is .

The nth term and the st term of the sequence are

and

The ratio(r) =

              (Substitute r = and )

          (Substitute r = and )

        (Substitute r = and )

The ratio of successive terms is the nonzero constant − 5 ,

The sequence is geometric with common ratio − 5 .

The sequence is geometric with common ratio − 5.

First four terms are − 5 ,  25 , − 125 ,  625.