not sure what the dots are supposed to mean..
but i think it's 6B5??
Answer:



Step-by-step explanation:
We are given the following recursive formula:

And consider 
a2

a3

a4

It is equal because every 2000 pounds is 1 ton and 18000lb divided by 2000 equals 9.
Inserting all the given information into the identity, we have
