Lets say that P is your starting principal (spelled -pal and not -ple, because Your Money is Your Pal), r is the interest rate (expressed as a decimal), and Y is the number of years you invest. Then your future value will be:
P (1 + rY) (Simple Interest)
P (1 + r)Y (Annually Compounded Interest)
Note the two formulas give the same answer for one year. After that, compound interest takes off.
The answer would be D) 9 + (-9) = 0 because additive inverse is a number added to its opposite to get zero so 9 is the additive inverse of -9 and -9 is the additive inverse of 9.
