Answer:
The first four terms of the sequence are-6, -2, 2 and 6
Step-by-step explanation:
The given sequence is 
In order to find the first four term of the sequence we put n =0, 1, 2 and 3.
For n =0

For n =1

For n =2

For n =3

Therefore, the first four terms of the sequence are
-6, -2, 2 and 6
685-85=600
1 year =12 months
12 multiply by 2 =24
600 divided by 24=25
answer=25