Answer
$E=-(-4p+33))\times\frac{p}{-2p^2+33p} = \frac{4p^2-33p}{-2p^2+33p}$
Work Step by Step
The demand function is $q=-2p^2+33p$ where ($9\leq p \leq 15$)
The elasticity can be calculated as:
$E=-\frac{dq}{dp}\times\frac{p}{q}$
The derivative of the demand function is :$\frac{dq}{dp}=-2\times2p+33=4p+33$ Therefore $E=-(-4p+33))\times\frac{p}{-2p^2+33p} = \frac{4p^2-33p}{-2p^2+33p}$
