The questions asks for a formula that determine how much you'll save for buying a specified amount of bottles. With this, we call ready know that the formula will begin as c= ____ because we see that c = the cost savings.
Next, we know that the regular price minus sales pricing will result in c; your cost savings. So now we can fill in the blanks as c = r - s.
We're almost complete! Now all we need to do is insert the amount of items you're buying into the equation. Since we want to know the c = cost savings, then all we need to do is insert 3 into the regular price and the sales price of the equation. SO it'll look like this: c = 3r - 3s.
Answer: c = 3r - 3s