Question

3 function f gives the distance of a dog from a post, in feet, as a function of time, in seconds, since its owner left.
find the value of f(20) and of f(140).
4 function c gives the cost, in dollars, of buying n apples. what does each expression or equation represent in this situation?
a. c(5) = 4.50
b. c(2)

Explanation:

Problem 3

Step1: Find \( f(20) \)

To find \( f(20) \), we look at the graph of the function \( f \) where the \( x \)-value (time in seconds) is 20. From the graph, when \( x = 20 \), the corresponding \( y \)-value (distance from post in feet) is 3. So \( f(20)=3 \).

Step2: Find \( f(140) \)

To find \( f(140) \), we look at the graph of the function \( f \) where the \( x \)-value (time in seconds) is 140. From the graph, when \( x = 140 \), the corresponding \( y \)-value (distance from post in feet) is 4 (or approximately 4, based on the graph's shape at \( x = 140 \)). So \( f(140)=4 \) (or the appropriate value from the graph's interpretation).

The function \( C(n) \) represents the cost (in dollars) of buying \( n \) apples. So \( C(5) = 4.50 \) means that when \( n = 5 \) (i.e., when buying 5 apples), the cost \( C \) is 4.50 dollars. In other words, the cost of buying 5 apples is $4.50.

Answer:

\( f(20) = 3 \), \( f(140) = 4 \) (values are based on the graph's interpretation for the respective \( x \)-values)

Problem 4a