#### Answer

$k'(x) = (288x)(12x^2+5)^{-7}$

#### Work Step by Step

In order to derivate this function you have to apply the chain rule
Let's make an «u» substitution to make it easier
$u = 12x^2+5$
$k(u) = -2u^{-6}$
Derivate the function:
$k'(u) = 12u^{-7}7u'$
Now let's find u'
$u' = 24x$
Then undo the substitution, simplify and get the answer:
$k'(x) = 12(24x)(12x^2+5)^{-7}$
$k'(x) = (288x)(12x^2+5)^{-7}$