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

D.  26.6 million phones per year

Step-by-step explanation:

Given: The equation 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

When  x=2

The annual increase =

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

-6 is the correct option from the above given options