To find the explicit formula for the sequence \(12, 6, 0, -6, \ldots\), let's first look at how the sequence changes.
The sequence starts at 12 and decreases by 6 each time:
- From 12 to 6, it decreases by \(6\).
- From 6 to 0, it decreases by \(6\).
- From 0 to -6, it decreases by \(6\).
This means it is an arithmetic sequence where:
- The first term \(A_1 = 12\),
- The common difference \(d = -6\).
The explicit formula for an arithmetic sequence can be expressed as:
\[ A_n = A_1 + (n-1)d \]
Substituting in our values:
\[ A_n = 12 + (n-1)(-6) \]
This corresponds to the option:
An=12+(n−1)(−6)
Thus, the correct answer is:
An=12+(n−1)(−6).