To represent the given geometric sequence \(6, 18, 54, \ldots\), we need to identify the first term and the common ratio.
- The first term \(a\) is \(6\).
- The second term divided by the first term gives the common ratio \(r\): \[ r = \frac{18}{6} = 3 \]
The general formula for the \(n\)-th term of a geometric sequence can be expressed as: \[ a_n = a \cdot r^{n-1} \] where \(a\) is the first term, \(r\) is the common ratio, and \(n\) is the term number.
For this sequence:
- \(a = 6\)
- \(r = 3\)
Thus, we can write the function representing the geometric sequence as: \[ f(x) = 6 \cdot 3^{x-1} \]
So, the correct response from the options provided would be: \[ f(x) = 6(3)^{x-1} \]
This represents the function correctly.