pleaseeee help i don't understand how to do this

Answer:
[tex]x=\frac{5}{k}[/tex]
Step-by-step explanation:
Given expression is,
[tex]\text{log}_{3^k}243=x[/tex]
By using the law of logarithm,
[tex](3^k)^x=243[/tex]
[tex]3^{kx}=243[/tex]
[tex]3^{kx}=3^5[/tex]
By comparing exponents on both the sides of the equation,
[tex]kx=5[/tex]
[tex]x=\frac{5}{k}[/tex]
Therefore, [tex]x=\frac{5}{k}[/tex] will be the answer.