Answer:
a/b = 2/3
Step-by-step explanation:
(81/16)^(-1/4) = (16/81)^1/4 = ((2^4)/(3^4))^(1/4) = (2^(4/4))/(3^(4/4)) = 2/3
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The applicable rules of exponents are ...
(a^b)^c = a^(bc)
a^-b = 1/(a^b)
And the reciprocal of a fraction is ...
1/(a/b) = b/a
