Question

URGENT NEEDS ANSWERED RIGHT AWAY Talk of the Town is a cell phone provider. They charge by the month. The first month of service costs $72.99. The second month of service costs $101.44. The third month of service costs $129.89. Write an equation in the form of y=c+d(x−1)
to represent this situation. Explain how you got your equation.

Answer 1

Answer:

$y=72.99+28.45(x-1).$

Step-by-step explanation:

If we are to write an equation of the form $y=c+d(x-1)$, then the function is linear; therefore, it has a constant slope $d$.

The slope $d$ of the function is given by

$d= \dfrac{\ 101.44-\ 72.99}{2-1}$

$\boxed{ d=28.45}$

thus we have

$y=c+28.45(x-1).$

Now we find $c$ from the fact that the first month of service costs $72.99, which gives us $(x,y)= (1, 72.99)$, or

$\ 72.99=c+28.45(1-1)$

$\boxed{c=72.99}$

Substituting the values of $d$ and $c$, we get our equation in the final form:

$\boxed{ y= 72.99+28.45(x-1)}$