Simplify x1(y2z7)3x8y5z6\displaystyle \frac{{{x}^{{1}}{\left({y}^{{-{{2}}}}{z}^{{7}}\right)}^{{3}}}}{{{x}^{{-{{8}}}}{y}^{{5}}{z}^{{-{{6}}}}}}

Write your answer with positive exponents only.