ANSWER :
A. 2
EXPLANATION :
From the problem, we have the function :
[tex]f(x)=3^x[/tex]
when f(x) = 9 :
[tex]\begin{gathered} f(x)=3^{^x} \\ 9=3^x \end{gathered}[/tex]
Note that 9 is 3^2
[tex]\begin{gathered} 9=3^x \\ 3^2=3^x \\ \text{ Since the bases are equal, the exponents are equal too.} \\ 2=x \\ x=2 \end{gathered}[/tex]
