Solution
Note: Formula for average rate on {a, b}
[tex]Average\text{ }Rate=\frac{f(b)-f(a)}{b-a}[/tex]
From the question, we have
[tex]\begin{gathered} a=-6 \\ b=-2 \\ f(a)=f(-6)=-2 \\ f(b)=f(-2)=-10 \end{gathered}[/tex]
Substituting the parameters
[tex]\begin{gathered} Average\text{ }Rate(A.R)=\frac{f(b)-f(a)}{b-a} \\ \\ A.R=\frac{-10-(-2)}{-2-(-6)} \\ \\ A.R=\frac{-10+2}{-2+6} \\ \\ A.R=\frac{-8}{4} \\ \\ A.R=-2 \end{gathered}[/tex]
Average Rate of change = -2
