What is the next term of the geometric sequence?
7, 21, 63

First find the common ratio of this geometric sequence.

We will use .

The second term is 21 and the first term is 7.

So we have and this reduces to or 3.

So, we take the last term in our geometric sequence

and multiply it by the common ratio we just found.

So we have 63 · 3 which is 189.

So the next term in this geometric sequence is 189.

-2

7 - 9 = -2

reversed:

-2 + 9 = 7