Question

Eliza started her savings account with $100. Each month she deposits $25 into her account. Write the function that describes the relationship between the amount Eliza deposits and the total amount in her account. Then, determine the average rate of change in the account from the 2nd month to the 10th month.

Answer 1

Okay, since she started with $100, then that would be a constant. So the function would start off with f(x)=?+100. Okay, now since she is depositing $25 PER month, then the 'x' varibale would be per month. So the function would be f(x)=25x+100. Now since you want to know the rate of change, just insert the x value as the month. For example, you want to know how much money she has on the 4th month, so you would substitute 4 with x --> f(x)=25(4)+100, which is f(x)=200