Please help me with this question!

$\phantom{=\,}(-8)^{-\frac23}\\ $

$=\,\frac{1}{(-8)^{\frac23}}$          because      $x^{-a}\,=\,\frac{1}{x^a}$

$=\,\frac{1}{(-8)^{\frac23}}\cdot\frac{(-8)^\frac13}{(-8)^\frac13}$

$=\,\frac{(-8)^{\frac13}}{(-8)^{\frac23+\frac13}}$          because     $x^a\cdot x^b\,=\,x^{a+b}$

$=\,\frac{(-8)^{\frac13}}{(-8)^{\frac33}}$

$=\,\frac{(-8)^{\frac13}}{(-8)^{1}}$

$=\,\frac{-2}{-8}$

$=\,\frac14$