Answer :

[tex]3^{x+6}=8[/tex]

Equations of this form are solved by first taking the natural logarithm (ln) of both sides. So:

[tex]\ln (3^{x+6})=\ln (8)[/tex]

We now use the property of logarithms shown below:

[tex]\ln (a^b)=b\ln (a)[/tex]

So, the equation becomes:

[tex]\begin{gathered} \ln (3^{x+6})=\ln (8) \\ (x+6)\ln (3)=\ln (8) \end{gathered}[/tex]

Distributing the value ln(3), we get:

[tex]\begin{gathered} (x+6)\ln (3)=\ln (8) \\ \ln (3)x+6\ln (3)=\ln (8) \end{gathered}[/tex]

Now, we solve for x:

[tex]\begin{gathered} \ln (3)x+6\ln (3)=\ln (8) \\ \ln (3)x=\ln (8)-6\ln (3) \\ x=\frac{\ln (8)-6\ln (3)}{\ln (3)} \\ x=\frac{\ln 8}{\ln 3}-6 \end{gathered}[/tex]

Looking at the answer choices,

D is the correct answer!