Answer:
[tex]x = \frac{log\ 243}{log\ 3}[/tex]
Step-by-step explanation:
Given
[tex]3^x = 243[/tex]
Required
Express as a logarithm
[tex]3^x = 243[/tex]
Take log of both sides
[tex]log\ 3^x = log\ 243[/tex]
Apply the following law of logarithm
[tex]log\ a^b = b\ log\ a[/tex]
So, the expression becomes:
[tex]log\ 3^x = log\ 243[/tex]
[tex]x\ log\ 3 = log\ 243[/tex]
Divide both sides by log 3
[tex]\frac{x\ log\ 3}{log\ 3} = \frac{log\ 243}{log\ 3}[/tex]
[tex]x = \frac{log\ 243}{log\ 3}[/tex]
Hence, the expression in base 10 is:
[tex]x = \frac{log\ 243}{log\ 3}[/tex] or [tex]x = \frac{log_{10}\ 243}{log_{10}\ 3}[/tex]