Chapter 7 - Section 7.4 - Adding, Subtracting, and Multiplying Radical Expressions - Exercise Set - Page 439: 38

$\dfrac{\sqrt[4]{3}}{5x}$

Using the properties of radicals, then, \begin{array}{l} \dfrac{\sqrt[4]{48}}{5x}-\dfrac{2\sqrt[4]{3}}{10x} \\\\= \dfrac{\sqrt[4]{16\cdot3}}{5x}-\dfrac{\sqrt[4]{3}}{5x} \\\\= \dfrac{2\sqrt[4]{3}}{5x}-\dfrac{\sqrt[4]{3}}{5x} \\\\= \dfrac{\sqrt[4]{3}}{5x} .\end{array}