Question

the graph below shows the total cost of using a music provider for one month depending on how many songs were downloaded.

Answer 1

Use the graph to find the equation for the total cost in terms of number of songs

1. Find the slope (m): Use the ordered pair of two points in the next formula:

`m=(y_2-y_1)/(x_2-x_1)`
`m=(18-15)/(2-0)=(3)/(2)`

2. Identify the y-intercept: Value of y when x is 0

y intercept (b): 15

3. Use the slope and y-intercept to write the equation of the line:

`\begin{gathered} y=mx+b \\ \\ y=(3)/(2)x+15 \end{gathered}`

___________

If Jeremaine downloads 75 songs in one month (x=75), to find the total cost evaluate the function for x=75:

`\begin{gathered} y=(3)/(2)(75)+15 \\ \\ y=112.5+15 \\ \\ y=127.5 \end{gathered}`Then, the total cost for the month is $127.50