D , because 28-9=21 and 21=x
Answer:
2317.2
Step-by-step explanation:
2327.2-10
=2317.2
Answer:
Step-by-step explanation:
Hello, this is a geometric sequence so we are looking for a multiplicative factor.

So, the explicit formula is for n

Hope this helps.
Do not hesitate if you need further explanation.
Thank you