Question

You bought 7 pencils for $2.45. Your friend bought 9 pencils for $3.15. Write an equation in POINT-SLOPE Form to model the total bill (y) in terms of the number of pencils purchased (x).

Answer 1

We can say that we have two points of the graph: (7, 2.45) and (9,3.15)

therefore we can calculate the slope of the function

`m=(3.15-2.45)/(9-7)=(0.7)/(2)=0.35`

so the equation is

`\begin{gathered} y-2.45=0.35(x-7) \\ y=0.35x-2.45+2.45=0.35x \end{gathered}`

In conclusion we have that the equation is

`y=0.35x`