Answer
$-6x^6+36x^3+54x$
Work Step by Step
Using $a(b+c)=ab+ac$ or the Distributive Property, the given expression, $
6x(-x^5+6x^2+9)
$, is equivalent to
\begin{array}{l}\require{cancel}
6x(-x^5)+6x(6x^2)+6x(9)
\\\\=
-6x^6+36x^3+54x
.\end{array}