Elementary Algebra

$\dfrac{8z}{7x}$
Cancelling the common factor between the numerator and the denominator, the given expression, $\dfrac{-56yz}{-49xy} ,$ simplifies to \begin{array}{l}\require{cancel} \dfrac{\cancel{-7y}\cdot8z}{\cancel{-7y}\cdot7x} \\\\= \dfrac{8z}{7x} \end{array}