It went from 10 to -2, so you need to find the difference. The way you'd do this is: 10 - (-2). Do you know how to subtract a negative number from a positive number?
Answer:
Step-by-step explanation:
2/8 = 1/4
2/8 = 200/800
and so on.
There are an infinite number of possibilities here.

The account will have decreased by $2640 after 2/3 year.
I have no clue if this is correct but the answer I got was 10,260,000