Pls help :) solve. b-^4 =1/81 b
\(b^{-4} =\frac{1}{81}\\\\b^{-4} =\frac{1}{b^4}\\\\\frac{1}{b^4}=\frac{1}{81}\\\\b^4 = 81\\\\b^4 = 3^4\\\\b^4 = (-3)^4\\\\\boxed{\bf{b = 3}}\\\\\boxed{\bf{b=-3}}\)
