Answer
$4x^\frac{1}{4}$
Work Step by Step
$$\frac{20x^{\frac{1}{2}}}{5x^\frac{1}{4}}$$
When two rational expressions with the same base are divided, subtract the exponents.
$$=(\frac{20}{5})(x^{(\frac{1}{2} - \frac{1}{4})})$$
When subtracting fractions, you need a common denominator, in this case, 4:
$$=4x^{(\frac{2}{4} - \frac{1}{4})}$$
$$=4x^{\frac{1}{4}}$$