Respuesta :
Answer:
 [tex]\dfrac{b^3}{8a^{18}}[/tex]  matches the first choice
Step-by-step explanation:
[tex]\left(\dfrac{2 a b}{a^{-5}b^2}\right)^{-3}=(2a^{1-(-5)}b^{1-2})^{-3}=(2a^6b^{-1})^{-3}\\\\=2^{-3}a^{6(-3)}b^{-1(-3)}=8^{-1}a^{-18}b^3=\boxed{\dfrac{b^3}{8a^{18}}}[/tex]
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The applicable rules of exponents are ...
 (a^b)(a^c) = a^(b+c)
 (a^b)^c = a^(bc)
 a^-b = 1/a^b