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 290 minutes, the monthly cost will be $87. If the customer uses 980 minutes, the monthly cost will be $225. A) Find an equation in the form y = m x + b , where x is the number of monthly minutes used and y is the total monthly of the A Fee and Fee plan.

Answer 1

y=0.2x+29

Explanation:

Given that:

y is the total monthly of the A Fee and Fee plan.

x is the number of monthly minutes used.

• If a customer uses 290 minutes, the monthly cost will be $87, we have the pair (290, 87)

• If the customer uses 980 minutes, the monthly cost will be $225, this is the coordinate pair (980, 225).

We want to obtain an equation in the form: y=mx+b

First, let us determine the slope, m

Given points (290, 87) and (980, 225):

Slope

`m=(225-87)/(980-290) =(138)/(690)=0.2`

Next, we determine the y-intercept, b.

Substituting the pair (290, 87) and m=0.2 in y=mx+b, we obtain

87=0.2(290)+b

b=87-0.2(290)=29

Therefore, our equation in the form y=mx+b is:

y=0.2x+29