5:7, 15:21. Hope this helps!!!
I believe this is the answer
A) 24
B) -3
WOWW LOL THNX THO teeeheee
Answer:

Step-by-step explanation:
An arithmetic sequence that is described by the explicit formula ...

can also be described by the recursive formula ...

Matching parts of the formulas, we see that a1 = 4, d = -7. Putting these values into the explicit formula gives ...

Step-by-step explanation:
please see the proof in the attachment above