#### Answer

$y' = -18x^{-7}-5x^{-6}+14x^{-3}$

#### Work Step by Step

In order to derivate this function you have to apply the power rule:
$\dfrac{d}{dx}(x^n)=nx^{n-1}$
But first let's rewrite the function
$y = 3x^{-6}+x^{-5}-7x^{-2}$
then
$y' = 3(-6)x^{-7}+(-5)x^{-6}-7(-2)x^{-3}$
$y' = -18x^{-7}-5x^{-6}+14x^{-3}$