What would the equation be if the points were 6,18 and -12,3

Problem 3 a bank charges a service fee of $7.50 per month for a checking account. a bank account has $85.00. if no money is deposited or withdrawn except the service charge, how many months until the account balance is negative

How many baseball cards did hayden buy?

What is (2.5a^8n)^3 · (0.4^7n)^3 can you plz simplify this quickly offering lots of points