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### Course: Algebra 1>Unit 8

Lesson 7: Recognizing functions

# Recognizing functions from verbal description word problem

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

## Want to join the conversation?

• 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
• Is it just me or does this make no sense :D
• Amount(shipping cost) is NOT a function. shipping cost (amount) IS a function because for any given amount there is only one possible output
• 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.
• is it possible to represent the amount of order as an input?
• 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.
• Well if
Shipping cost(y) is output and
amount of order(x) is input, then
y=4 when x<20, and
y=7 when x>20.
This means that the shipping cost is the function for the amount of dollar right?
Cos various inputs can have one output but one input can't have various outputs in functions. Right?