Find a formula for the general term a_n of the sequence:

{-3, 2, - 4/3, 8/9, - 16/27}

First of all, we need to put the first two numbers into fraction form:

{-3/1, 2/1, - 4/3, 8/9, - 16/27}

You can see there is a pattern to these numbers, and the pattern is that each number is multiplied by - 2/3 to give the following number (-3 * (-2/3) = 2; 2 * (-2/3) = - 4/3, and so on).

This means that this is a geometric sequence.