Answer
$p'(x) = 5x^{-3/2}-12x^{-5/2}$
Work Step by Step
In order to derivate this function you have to apply the power rule:
$\dfrac{d}{dx}(x^n)=nx^{n-1}$
$p'(x) = -10(-\dfrac{1}{2})x^{-3/2}+8(-\dfrac{3}{2})x^{-5/2}$
$p'(x) = 5x^{-3/2}-12x^{-5/2}$