To represent the geometric sequence 6, 18, 54, ..., we first identify the first term and the common ratio of the sequence.
- The first term \( a_1 \) is 6.
- The common ratio \( r \) can be found by dividing the second term by the first term: \[ r = \frac{18}{6} = 3 \]
- The general formula for the nth term of a geometric sequence is given by: \[ a_n = a_1 \cdot r^{n-1} \] where \( n \) is the term number starting from 1.
In this case, substituting \( a_1 = 6 \) and \( r = 3 \): \[ a_n = 6 \cdot 3^{n-1} \]
Thus, the function representing the sequence can be written as: \[ f(x) = 6(3)^{x-1} \]
So, the correct response is: f(x) = 6(3)^{x-1}