Question

se log4x= 0,9 quanto vale o log 8x?

Answer 1

$log4x=log4+logx=0,9 \Rightarrow logx=0,9-log4\\ \\ log8x=log8+logx=log8+0,9-log4=0,9+0,9-0,6=1,2$

Answer 2

Olá, Estereds.

$\log8x=\log(2\cdot4x)=\log2+\log4x=\log2+0,9=0,3+0,9=\boxed{1,2}$