find the fifth term of geometric sequence

Question

a=-6 r=2

This website explains how to do it:

http://www.mathguide.com/lessons/SequenceGeometric.html

However, you must designate which term in the sequence is what you call "a". Is it the f1rst term, a1? If so,

a2 = r* a1 = -12.. etc.

3 1
_______ - _______
x-3 x