Question

 calcule o valor da base a  log a 243 = 5

Answer 1

$log_{b}(a)=c <=> b^{c}=a$
__________________________

$log_{a}(243)=5$
$a^{5}=243$
$a^{5}=3^{5}$
$a=3$

Answer 2

log(a) 243 = 5
Decompondo 243:
243|3
081|3
027|3
009|3
003|3
001 --> 243 = 3^5
Logo, log(a)243 = 5 --> log(a)3^5 = 5 --> 5.log(a)3 = 5 --> log(a)3 = 1 --> a = 3