# Chapter 2 - Graphs and Functions - 2.4 Linear Functions - 2.4 Exercises - Page 229: 65

The average rate of change is $-\$4000$. The value of the machine depreciates at an average of$\$4000$ per year.

#### Work Step by Step

The graph is from $x=0$ to $x=4$ so the interval is $[0, 4]$. RECALL: The average rate of change in the interval $[a, b]$ is given by the formula: average rate of change = $\dfrac{f(b)-f(a)}{b-a}$ The given graph has $f(0) = 20$ and $f(4) = 4$. Thus, the average rate of change in the interval $[0, 4]$ is: $=\dfrac{f(4)-f(0)}{4-0} \\=\dfrac{4-20}{4} \\=\dfrac{-16}{4} \\=-4$ Therefore, the value of the machine depreciates at an average of $\$4000\$ per year.

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.