To evaluate the function \( f(x) = 3^x - 4 \) at \( x = 2 \), we can substitute 2 into the function:
\[ f(2) = 3^2 - 4 \]
Calculating \( 3^2 \):
\[ 3^2 = 9 \]
Now substitute that back into the equation:
\[ f(2) = 9 - 4 \]
\[ f(2) = 5 \]
It seems that none of the provided responses (1, 2, or 9) match our calculation of \( f(2) \). The correct answer should be \( f(2) = 5 \).