Question

Help!
Resolva a equação exponencial :

27 elevado à x-1 = 81 elevado à -x+3

:)

Answer 1

$27^{x-1} = 81^{-x+3}$
$(3^{3} )^{x-1} = (3^{4})^{-x+3}$ 
$3^{3x-3}= 3^{-4x+12}$
$3x-3=-4x+12$
$3x+4x=12+3$
$7x=15$
$x= \frac{15}{7}$