Question

The equation y = 26.6x - 14.5 is used to model the worldwide smartphone sales, y, in millions, each year, x, for a given company in its first 7 years selling smartphones. According to the model, what is the annual increase in the smartphone sales over this time period?

A.
3.8 million phones per year

B.
12.1 million phones per year

C.
14.5 million phones per year

D.
26.6 million phones per year

Answer 1

Answer: D. 26.6 million phones per year

Explanation:

Given: The equation
`y=26.6x-14.5` is used to model the worldwide smartphone sales (y) in millions, each year (x) for a given company in its first 7 years selling smartphones.

Here the slope of the linear function(coefficient of x) = 26.6

Since, slope is the rate of change of the variables.

Therefore,the annual increase in the smartphone sales over this time period= 26.6 millions phones per year.

OR

When x=1

`y=26.6(1)-14.5=12.1`

When x=2

`y=26.6(2)-14.5=53.2-14.5=38.7`

The annual increase =
`38.7-12.1=26.6`

hence, the annual increase in the smartphone sales over this time period= 26.6 millions.