Question

the function y=5.45 + 1.05(x+7) can be used to determine the cost of in dollars for a prepaid cell phone plan of x minutes. What is the rate if change of the cost, in dollars, with respect to the number of minutes purchased?​

Answer 1

The rate is 1.05

Step-by-step explanation:

Given

`y=5.45 + 1.05(x+7)`

Required

Determine the rate

`y=5.45 + 1.05(x+7)`

Open brackets

`y = 5.45 + 1.05 * x + 1.05 * 7`

`y = 5.45 + 1.05x + 7.35`

Collect like terms

`y = 1.05x + 7.35 + 5.45`

Simplify like terms

`y = 1.05x + 12.80`

The general equation is represented as:

`y = mx + b`

Where

`m = rate`

By comparing
`y = mx + b` to
`y = 1.05x + 12.80`

`m = 1.05`

Hence, the rate is 1.05