Question

3. While surfing the Internet, you find a site that claims to offer "the mostpopular and the cheapest DVDs anywhere." Unfortunately, the website isn'tclear about the how much they charge for each DVD, but it does give you thefollowing information:Number of DVDs Ordered1 is $15 Two DVD - $24 and Three DVD $33(includes S&H)$15 $24 $33a. Plot the points and connect them to form a line.b. What is the slope of the line containing the data points?c. What does the slope represent in this problem?d. What is the y-intercept of the line that contains the data points?

Answer 1

Data:

You have two variables: number of DVDs and cost. The cost is the dependient variable as depend of the number of DVDs. Then in a x-y plane you put in the x-axis the number of DVDs and in the y-axis the cost:

The slope can be find with the next formula:

`m=((y_2-y_1))/((x_2-x_2))`

You use two points:

`m=(24-15)/(2-1)=(9)/(1)=9`The slope is 9The slope represents the change on the cost in relation with the number of DVDs.

The y-intercept can be find using the general formula of the slope inercept lineal equation:

`y=mx+b`

Where m is the slope and b the y-intercept.

You know the value of m, and use a given point to find the y-intercpt:

Point (1,15)

`15=9(1)+b`
`15-9=b`
`6=b`

The y-intercept is: 6 and represents the value of the variable in the y-axis when x=0