$5$:$35$

$5$G

$/7$ Points$]$

Write a derivative formula for the function.

$f(x)=\frac{12\mathrm{.}2({4\mathrm{.}2}^x)}{x^2}$

$f^{\text{'}}(x)=$

$$

$/10$ Points$]$

A store has determined that the number of BI

$n(x)=6750({0\mathrm{.}931}^x)$ movies

where $x$ is the average price in dollars.

$($a$)$ Write the function for the model g

$R(x)=$ dollars

$($b$)$ If each movie costs the store $$10.$