The initial cost of an office fax machine is $100. after 1 year, its value becomes $80. which is the correct linear depreciation model?

Step-by-step explanation:

Let the x-axis be the time (in years) and the y-axis the value of the fax machine (in dollars).

We know that the initial value of the fax machine is $100; in other words, when the time is zero years, the value is $100, or as an ordered pair (0, 100). We also know that after 1 year the value decreases to $80, so (1, 80).

Now we can find the slope of the line passing through those two points using the slope formula

where

is the slope

are the coordinates of the first point

are the coordinates of the second point

Replacing values:

Now, to complete our model we are using the point slope formula

where

is the slope

are the coordinates of the first point

Replacing values:

We can conclude that the correct linear depreciation model is

the 3rd on is correct

step-by-step explanation: