Answer
$\dfrac{256}{81}$
Work Step by Step
$\bf{\text{Solution Outline:}}$
Use the laws of exponents to simplify the given expression, $
\left( \dfrac{27}{64} \right)^{-4/3}
.$
$\bf{\text{Solution Details:}}$
Using the extended Power Rule of the laws of exponents which states that $\left( \dfrac{x^m}{z^p} \right)^q=\dfrac{x^{mq}}{z^{pq}},$ the expression above is equivalent to
\begin{array}{l}\require{cancel}
\dfrac{27^{-\frac{4}{3}}}{64^{-\frac{4}{3}}}
.\end{array}
Using the Negative Exponent Rule of the laws of exponents which states that $x^{-m}=\dfrac{1}{x^m}$ or $\dfrac{1}{x^{-m}}=x^m,$ the expression above is equivalent to
\begin{array}{l}\require{cancel}
\dfrac{64^{\frac{4}{3}}}{27^{\frac{4}{3}}}
.\end{array}
Using the definition of rational exponents which is given by $a^{\frac{m}{n}}=\sqrt[n]{a^m}=\left(\sqrt[n]{a}\right)^m,$ the expression above is equivalent to
\begin{array}{l}\require{cancel}
\dfrac{(\sqrt[3]{64})^4}{(\sqrt[3]{27})^4}
\\\\=
\dfrac{(\sqrt[3]{4^3})^4}{(\sqrt[3]{3^3})^4}
\\\\=
\dfrac{(4)^4}{(3)^4}
\\\\=
\dfrac{256}{81}
.\end{array}
