Respuesta :

The Solution.

Given the function below:

[tex]f(x)=\frac{1}{x+9}\text{ and the interval \lbrack{}10,10+h\rbrack}[/tex]

The average rate of change in the given interval is

[tex]\text{Average rate of change}=\frac{f(b)-f(a)}{b-a}[/tex]

In this case,

[tex]a=10,b=10+h[/tex]

So,

[tex]f(a)=f(10)=\frac{1}{10+9}=\frac{1}{19}[/tex][tex]f(b)=f(10+h)=\frac{1}{10+h+9}=\frac{1}{19+h}[/tex]

Substituting in the formula, we have

[tex]\text{Average rate of change =}\frac{\frac{1}{19+h}-\frac{1}{19}}{10+h-10}[/tex][tex]\begin{gathered} \text{Average rate of change =}\frac{\frac{19-(19+h)}{19(19+h)}}{h}=\frac{-h}{19h(19+h)}=\frac{-1}{19(19+h)} \\ \end{gathered}[/tex]

So, the correct answer is

[tex]\frac{-1}{19(19+h)}[/tex]

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