Four years ago you invested some money at 10% interest. You now have $439.23 in the account. If the interest was compounded yearly, how much did you invest 4 years ago?
possibly last question, thanks so much!
We need to solve this for A, the amount originally invested....
439.23 = A(1.10)^4 divide both sides by (1.10)^4
439.23 / (1.10)^4 = A = $300
+1449 
