Answer
$\dfrac{1}{x^5}$
Work Step by Step
Using the laws of exponents, the given expression, $
\dfrac{x^3}{(x^4)^2}
,$ simplifies to
\begin{array}{l}\require{cancel}
\dfrac{x^3}{x^{4(2)}}
\\\\=
\dfrac{x^3}{x^{8}}
\\\\=
x^{3-8}
\\\\=
x^{-5}
\\\\=
\dfrac{1}{x^5}
.\end{array}