Question

Jasmine invests 2658 in a retirement account with a fixed annual interest rate of 9% compounded annually what will the account balance be after 4 years

Answer 1

Without making a function out of it, all you need to do is the initial amount 2658$ x 1.09 (1,09 is like adding 0,09 to the total amount 1,00. Which, in % is adding 9% to the total amount 100%.)
= 2897.22$

Since it is compounded every year, you redo the same operation but on the new higher sum you just got.

In total, after 4 years you will have 3751,98$