The price of a certain product changes with time, beginning with its release in 2009. In 2018, the product costs $44. Later, in 2021, the product costs $21.
If a linear model is used to describe the way the price (y) changes depending on the number of years since 2009 (x), what is the slope of this model? (Answer choices below are rounded to two decimal places.)
O-7.67
7.67
0.13
-0.13
Undefined
To find the slope of the linear model, we first need to determine the change in price (Δy) over the change in years (Δx).
The change in price would be $21 - $44 = -$23
The change in years would be 2021 - 2009 = 12 years
Now, we can calculate the slope using the formula:
slope = Δy / Δx
slope = -23 / 12
slope = -1.92
Rounded to two decimal places, the slope is approximately -1.92. Therefore, the correct answer choice is:
-0.13