Shelley wants to purchase a cell phone package, which includes a free phone. The cost of the package is $0.10 per minute, for the number of minutes she uses the phone, plus a base rate of $89.00.

The function would be linear because the rate of change is constant.

Step-by-step explanation:

Given

per minute

See attachment for complete question and options

First, we write the function that calculates the cost (C(t)) for t minutes.

This is calculated as:

Rewrite as:

A function that has the above format is referred to as a linear function which has the general format

Where

m represents the slope/rate and it is constant

From the list of given options, (a) is correct.

check the picture below.

well, the angle at the vertex d is clearly not a right-angle, let's check for the one at the vertex f which does look like,   however if it's indeed, that means ef is perpendicular to df, in which case their slopes will be negative reciprocal of each other.

so the negative reciprocal of the slope of ef is 1, however the slope of df is not 1, is 1/2, so nope, they're not perpendicular lines.