Question

Write a situation that can be modeled by the following equation:f(x) = -5x + 15

Answer 1

The equation we have is:

$f(x)=-5x+15$

A situation that can be modeled by the function is:

A girl starts with $15 to spend, and x is the number of chocolate bars she buys.

Each chocolate bar costs $5.

In this situation f(x) represents the amount she has left after buying x number of chocolate bars.

$f(x)=-5x+15$

here we have that 15 is the amount of money she starts with, and we subtract 5 for every chocolate bar she buys.

For example, if she buys 3 chocolate bars x=3, she will have left:

$\begin{gathered} f(3)=-5(3)+15 \\ f(3)=-15+15 \\ f(3)=0 \end{gathered}$

She will have $0 left.

Of course, if she buys more candy bars the value of f(x) will become negative and will represent the money she owes.