Answer
$\dfrac{y^{14}}{x^{12}z^{7}}$
Work Step by Step
Using laws of exponents, the expression $
\left( x^{-5}y^2z^{-1} \right)^{7}
$ simplifies to
\begin{array}{l}
x^{-5(7)}y^{2(7)}z^{-1(7)}
\\\\=
x^{-12}y^{14}z^{-7}
\\\\=
\dfrac{y^{14}}{x^{12}z^{7}}
.\end{array}
