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

$m=\frac{3.15-2.45}{9-7}=\frac{0.7}{2}=0.35$

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

$y=0.35x$