can someone help me with #6a

Answer:
an = an-1 *4
Step-by-step explanation:
To find the common ratio, we take the second term and divide it by the first
12/3 = 4
We check this by taking the third term and dividing by the second
48/12 =4
The common ratio is 4
The formula for a geometric sequence is
an = an-1 *r
where r is the geometric ratio
an = an-1 *4
The next term is the previous term * 4