Answer:
[tex]\frac{1}{4}[/tex]
Step-by-step explanation:
Using the rule of exponents / radicals
[tex]a^{\frac{m}{n} }[/tex] = [tex](\sqrt[n]{a})^m[/tex]
[tex]a^{-m}[/tex] = [tex]\frac{1}{a^{m} }[/tex] , then
[tex]-8^{-\frac{2}{3} }[/tex]
= [tex]\frac{1}{-8^{\frac{2}{3} } }[/tex]
= [tex]\frac{1}{(\sqrt[3]{-8})^2 }[/tex]
= [tex]\frac{1}{-2)^{2} }[/tex]
= [tex]\frac{1}{4}[/tex]