Answer
$\dfrac{x^{-3}}{y^{-7}} =\dfrac{y^7}{x^3}$
Work Step by Step
RECALL:
The negative-exponent rule of exponents states that:
$a^{-m} =\dfrac{1}{a^m}$ and $\dfrac{1}{a^{-m}} = a^m$, where $a \ne 0$.
Use the negative-exponent rule to find:
$\dfrac{x^{-3}}{y^{-7}} =\dfrac{\frac{1}{x^3}}{\frac{1}{y^7}}=\dfrac{1}{x^3} \cdot \dfrac{y^7}{1}=\dfrac{y^7}{x^3}$
