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allie193
11-03-2008, 10:19 PM
The relationship between the selling price of a sleeping bag, s dollars, and the revenue at that selling price, r(s) dollars, is represented by the function r(s)=-10s^2 + 1500s. Evaluate, interpret, and compare r(29.95), r(60.00), r(75.00), r(90.00), and r(130.00).

This question is much different from the other questions in my functions unit so I am not sure where to even begin with this. If I fill in what I know I still am not sure what to do from there:
29.95=-10s^2 + 1500s

Would I solve it using the quadratic formula? It isn't used at all in this unit but seems the most likely to me. If so, would it be like this:

0=-10s^2 + 1500s - 29.95

or would I want to switch the negatives so that (a) is not negative like this:

10s^2 - 1500s + 29.95=0

(Or can I even do that? :oops: )

Thanks for any help!

Denis
11-03-2008, 10:36 PM
10s^2 - 1500s + 29.95=0

Yes, that's a GOOD way: have more confidence in yourself :wink:
And yes, use the quadratic...

fasteddie65
11-04-2008, 08:35 AM
"the function r(s)=-10s^2 + 1500s. Evaluate, interpret, and compare r(29.95), r(60.00), r(75.00), r(90.00), and r(130.00)"

You are working way too hard. r(29.95), for example, means to substitute 29.95 for s in the equation r(s) = -10s^2 + 1500s. So r(29.95) = -10(29.95)^2 + 1500(29.95) = 35954.975. This means the revenue from selling at $29.95 each would be approximately $35,954.98.

allie193
11-28-2008, 05:37 PM
I just wanted say thanks and that I did get the right answer on my assignment! :D Thanks again!