For the sequence $5, 25, 125, 625, …$

1. What kind of sequence is it?

   Hint (a):

   What mathematical operation do you use to find the next term?

   Answer (a):

   Geometric.

2. What is the fifth term, $a_5$?

   Answer (b):

   $3,125$

3. Write an explicit equation for the sequence.

   Hint (c):

   The pattern of the sequence is
   $5\\5 \times 5\\5 \times 5 \times 5\:...$