Question

The phone company A Fee and Fee has a monthly cellular plan where a customer pays a flat monthly fee and then a certain amount of money per minute used on the phone. If a customer uses 130 minutes, the monthly cost will be $57. If the customer uses 780 minutes, the monthly cost will be $187. A) Find an equation in the form y = m x + b , y = m x + b , where x x is the number of monthly minutes used and y y is the total monthly of the A Fee and Fee plan.

Answer 1

Answer: The equation is in the form of $y=mx+c$ is $y=\frac{1}{5}x +31$.

Explanation:

We have to find the equation in the form of $y=mx+c$. It is a linear equation.

Where, x is the number of monthly minutes used and y is the total monthly of the A Fee and Fee plan.

If a customer uses 130 minutes, the monthly cost will be $57. If the customer uses 780 minutes, the monthly cost will be $187. When the data is written in the form of coordinate pairs we get (130,57) and (780,187).

The equation of line passing through two points $P(x_1,y_1)$ and $Q(x_2,y_2)$ is given below,

$y-y_1=\frac{y_2-y_1}{x_2-x_1}(x-x_1)$

We have two points (130,57) and (780,187) so the equation of line is,

$y-57=\frac{187-57}{780-130}(x-130)$

$y=\frac{1}{5}(x-130)+57$

$y=\frac{1}{5}x-26+57$

$y=\frac{1}{5}x+31$

Therefore, the equation is in the form of $y=mx+c$ is $y=\frac{1}{5}x +31$.