Chapter 5 - Section 5.2 - More Work with Exponents and Scientific Notation - Exercise Set - Page 268: 41

$\dfrac{x^4}{4z^2}$

Using laws of exponents, the given expression simplifies to \begin{align*} & \dfrac{4^{-1}x^2yz}{x^{-2}yz^3} \\\\&= 4^{-1}x^{2-(-2)}y^{1-1}z^{1-3} \\&= 4^{-1}x^{4}z^{-2} \\\\&= \dfrac{x^4}{4z^2} .\end{align*}