Question

(FUVEST-SP) Resolva Log10 (x) + 2.Logx (10) = 3.

Answer 1

 log x +2 (log10 / logx) = 3 (tudo na base 10) 

log x + 2/log x = 3 ..... MMC log x 

(Log x)^2 + 2 = 3logx 

Log^2 x - 3 log x + 2 = 0 faz: log x = k e aplica Baskara 

K^2 - 3K + 2 = 0 

K´= 2 =======> log x = 2 ==> 10^2 = x ===> x = 100 

K" = 1 ======> log x = 1 ==> 10^1 = x ===> x = 10

Espero ter ajudado