Answer
$\dfrac{25x}{8}$
Work Step by Step
The given expression, $
\left( \dfrac{x+2}{2x}-\dfrac{x-2}{2x} \right)\cdot\left( \dfrac{5x}{4} \right)^2
,$ simplifies to
\begin{array}{l}\require{cancel}
\dfrac{x+2-(x-2)}{2x}\cdot\dfrac{25x^2}{16}
\\\\=
\dfrac{x+2-x+2}{2x}\cdot\dfrac{25x^2}{16}
\\\\=
\dfrac{4}{2x}\cdot\dfrac{25x^2}{16}
\\\\=
\dfrac{\cancel{4}}{2\cancel{x}}\cdot\dfrac{25\cancel{x}\cdot x}{\cancel{4}\cdot4}
\\\\=
\dfrac{25x}{8}
.\end{array}
