This is almost the same as the other two. Really, throw us a bone, here. You can't have NO idea.
I'm hearing a voice of desperation. You need a voice of hope in your head.
You START with "Basic Principles". Really!! Forget the silly formulas.
"Jackson deposits $210"Jackson deposits $210 each month into a savings account earning interest at the rate of 7% per year compounded monthly. How much will he have in this account at the end of 6 years?
P = 210
n = 12
"earning interest at the rate of 7% per year"
i = 0.07
j = i/n = i/12 = 0.00583333
Accumulate One Month
a = 1+j = 1.00583333
I haven't even read the question, yet, and just look at all the stuff that is available! This is how you start. Collect the pertinent data.
"How much will he have in this account at the end of 6 years? "
6 years = 6*n = 72 months
We are ready to build!
P*r^72 + P*r^71 + ... + P*r = S = The desired result.
The rest is algebra.
P*(r^72 + r^71 + ... + r) = S
Your task is to add up the geometric series in the parentheses.
If you cannot do it, you may be in the wrong class. Give it some thought. If all you can do is tell us that you cannot do anything, that is not encouraging and you should have a very clear conversation with your academic advisor. You will not get anywhere here or in school without the necessary background.