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Recognizing functions from verbal description word problems

Checking whether a description of the price of an order can be represented as a function of the shipping cost. Created by Sal Khan.

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• Can the shipping cost be represented as a function of the dollar amount of the order?
• Yes, because when you input the dollar amount of the order you will get one price for shipping. So we would see that when x<20 then f(x) =4 and when x≥20 then f(x) = 7
• Amount(shipping cost) is NOT a function. shipping cost (amount) IS a function because for any given amount there is only one possible output
• Is it just me or does this make no sense :D
• Shouldn't the input be the shipping order? Why is it the shipping cost?
• because the question is asking "Can the dollar amount of the order be represented as a function of shipping cost?" The word represented means the opposite! so that's why shipping cost is the input! good question Varin Nair!
• Am i right in saying that the shipping cost can be represented as a function of the amount of the order?
• I think it can be a function!

``f(order) = shipping costif order < \$20 --> shipping cost \$4if order >= \$20 --> shipping cost \$7``

As you can see, no matter what number you give as an input you only have one possible output. An order can't have a shipping cost of \$7 AND \$4 at the same time.
• hello I need help learning math
• There are a lot of KA users that reply to posted questions. So, to get help, post a specific question about the video about what you don't understand. You will most likely get a response.
• it wont let me go on to my next lesson even tho i already did this one twice :(
• Sounds like you need technical support -- Use the "Help Center" link that is at the bottom of all KA screens.
• Hi everyone, Can anyone tell me why shipping cost is an input...
• Wait but I thought, x can't repeat but only y can. Isn't that what's happenign?
(1 vote)
• But 𝑥 is repeating.
𝑦 = 1 ⇒ 𝑥 = 4.
𝑦 = 2 ⇒ 𝑥 = 4.
We have the same 𝑥-value for different 𝑦-values.
Thereby 𝑦 is not a function of 𝑥.