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:
[tex]m=\frac{(y_2-y_1)}{(x_2-x_2)}[/tex]
You use two points:
[tex]m=\frac{24-15}{2-1}=\frac{9}{1}=9[/tex]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:
[tex]y=mx+b[/tex]
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)
[tex]15=9(1)+b[/tex][tex]15-9=b[/tex][tex]6=b[/tex]
The y-intercept is: 6 and represents the value of the variable in the y-axis when x=0
