Question

Solve for b b^-4=1/81^=exponent -4

Answer 1

$b^{-4}= \frac{1}{81} \\ \\ \frac{1}{b^4} = \frac{1}{81} => \\ \\ b^4=81 \\ b^4=3^4=>b=3$

Answer 2

1 / ( b^ 4 ) = 1 / 81 ;
b^4 = 81 ;
b^4 = 3^4 ;
b = + 3 or b = - 3 ;