Sophia invested some money in a bank at a fixed rate of interest compounded annually. The equation below shows the value of her investment after x years:

f(x) = 500(1.05)x

What was the average rate of change of the value of Sophia's investment from the second year to the fourth year?
14.13 dollars per year
28.25 dollars per year
50.00 dollars per year
56.50 dollars per year

Question

Sophia invested some money in a bank at a fixed rate of interest compounded annually. The equation below shows the value of her investment after x years:

f(x) = 500(1.05)x

What was the average rate of change of the value of Sophia's investment from the second year to the fourth year?
 14.13 dollars per year 
28.25 dollars per year 
50.00 dollars per year  
56.50 dollars per year

anonymous · Answer

@Mertsj could you help me?

mertsj · Answer

1.  Replace x with 4
2.  Replace x with 2
3.  Subtract the answer to Step 2 from the answer to Step 1
4.  Divide the answer to Step 3 by 2

anonymous · Answer

I don't understand how to do that though....

mertsj · Answer

You don't understand how to do what?  Substitute 4 in place of x?

anonymous · Answer

all of it

mertsj · Answer

Then do the first step and quit.

anonymous · Answer

@Jhannybean

jhannybean · Answer

Just follow exactly what @Mertsj stated. Put in 4 for x.

jhannybean · Answer

First.

anonymous · Answer

alright

mertsj · Answer

What did you get for 500(1.05)^4