Answer
$\dfrac{4t^{10}}{9s^{8}}$
Work Step by Step
Using the laws of exponents, the given expression, $
\left( \dfrac{2t^5}{3s^4} \right)^2
,$ simplifies to
\begin{array}{l}\require{cancel}
\dfrac{2^2t^{5(2)}}{3^2s^{4(2)}}
\\\\=
\dfrac{4t^{10}}{9s^{8}}
.\end{array}
