Question

A)$3^{x-3} =1/ \sqrt[3]{9}$    
OBS: preciso da resposta completa não so do resultado 

Answer 1

$3^{x-3} = \frac{1}{ \sqrt[3]{9} }$

$3^{x-3} = \frac{1}{9^{\frac{1}{3}}}$

$3^{x-3} = \frac{1}{3^{\frac{2}{3}}}$

$3^{x-3} = 3^{ \frac{-2}{3}$

$x - 3 = \frac{-2}{3}$

$x = \frac{-2}{3} + 3$

$\boxed{x = \frac{-2+9}{3} = \frac{7}{3}}$

Espero ter ajudado. :))

Answer 2

$3^{x-3}=\frac{1}{ \sqrt[3]{9} } \\ \\ 3^{x-3}=\frac{1}{ \sqrt[3]{3^2} } \\ \\ 3^{x-3}=\frac{1}{3^{\frac{2}{3}}} \\ \\ 3^{x-3}=3^{-\frac{2}{3}} \\ \\ x-3=-\frac{2}{3}\\ \\ x=-\frac{2}{3}+3 \\ \\ x=\frac{7}{3}$