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### Course: Algebra 1>Unit 8

Lesson 4: Interpreting function notation

# Function notation word problem: beach

Learn how to interpret expressions that contain a function within a real-world context. In this video, the function we interpret models the number of people at the beach over time.

## Want to join the conversation?

• Wouldn't it be obvious that there would be more ppl at 5 am than 9 am? It seemed obvious to me.
• That's not the point of the question. It is just an example to allow us to develop a stronger understanding of functions before we tackle harder real-life situations that don't seem as "obvious".
• Hey guys! This might not be the right place to ask this question but I am having trouble figuring out what to do with a question given to me by my math teacher. The equation is g(x) = 3x^2 + x and it says find x, if g(x) =2, how would I solve this any suggestions?
• 3x^2 + x = 2. then just solve for x. But I don't think this will help as your assignment would be 2 years late.
• hello can someone help me out with this question :

What does this mean?

g(x) has y-values greater than f(x) for x-values between -2 and 2. What will the mathematical notation be for this?

I don't understand
• My guess is this :- g(x) > f(x), when x = {-1,0,1}
• In 1980 high school dropouts were 5212 thousand. by 2008 the number dropped to 3118 thousand. what's the linear function that models the decrease?
• I'm not sure but I'll try. The number of dropouts (say d) is dependent on the year (say y). So d will be a function of y, f(y)=d and since the number d appears to decrease by 74,785 per year since 1980, d for the current year would be less by f(y)=74,785 (y-1980)
• At choice C, we wouldn't know if there were more people at the beach at 9am than there were at 5am! So wouldn't choice C be incorrect?
• You aren't asked to verify the accuracy of the statement. You are asked to interpret what it means. Item C is the correct interpretation for what the statement is saying.
• At , how would choice B be incorrect if 5am is an earlier time than 9am?
• You need to interpret the statement: p(5)<p(9)
This is not comparing time. This compares the output of the functions, which is numbers of people at the beach at 5am vs at 9am. So, you need to pick an answer that is related to people.

The expression is saying there are fewer people on the beach at 5am than at 9am. This is item C, but in reverse.
• Kaori is taking a free-throw.

H(d) models the basketball's height (in meters) at a horizontal distance of d meters from Kaori.

What does the statement H(R) = 4 mean?

(Choice A) At a horizontal distance of 4 meters from Kaori, the ball's height was equal to R meters.
(Choice B) The ball was at the same height at the horizontal distances of 4 meters and R meters.
(Choice C) At a horizontal distance of R meters from Kaori, the ball's height was equal to 4 meters.

Where does the variable R come from?