5. 3, 12, 48, 192, 768, ...
You can find the 15th term by using the formula
, where 
is the first term of the sequence, r is the common ratio, and n is the number of the term you want to find.
<span> Plug in your information (the common ration is x4)
</span>
Simplify the exponent
Multiply
The 15th term of the sequence is <span>805306368.
6. 200, 40, 8, 1.6, ...
Using guess and check, I found that the pattern here is </span>÷5, ÷5, ÷5, .... That can also be written as ×
, ×, <span>×, ... When you are multiplying the terms of a sequence, that is a geometric sequence.
</span>
You can find the 15th term by using the formula
<span>
</span>
The 15th term of the sequence is <span>805306368.
6. 200, 40, 8, 1.6, ...
Using guess and check, I found that the pattern here is </span>÷5, ÷5, ÷5, .... That can also be written as ×
</span>
