# Mathematics, Functions, Linear Functions

by LII

(United States)

Can You please help me with these 3 questions?

Which of the following are functions? The last two problems, i.e., b & c, are multi part relations consider all parts when determining whether or not these relations are functions. Explain your reasoning for a, b, and c.

a. f(x) = x + 3

b. f(x) = 73 if x>2 otherwise f(x) = -1

c. f(x) = 79if x>0 or f(x) = -9 if x<0 or f(x) = 9 or -9 if x = 0

Suppose you have a lemonade stand, and when you charge $1 per cup of lemonade you sell 48 cups. But when you raise your price to $2 you only sell 27 cups. Write an equation for the number of cups you sell as a function of the price you charge. Denote "C" for number of cups, and "P" for the price you charge. Assume the function is linear. Show your work.

Take a look at the table below and write out an equation for f(x). Show your work.

x -3 -2 1 3 4

f(x) 0 3 12 18 21

For each of the relationships below, explain whether you think it is best described by a linear function or a non-linear function. Explain your reasoning thoroughly

a. A person's height as a function of the person's age (from age 0 to 100)

b. The probability of getting into a car accident as a function of the speed at which you drive

c. The time it takes you to get to work as a function the speed at which you drive