Algebra-1

To find the explicit formula for the sequence 12, 9, 6, 3, ..., follow these steps:

Identify the common difference:

Calculate the differences between consecutive terms:

9−12=−3

6−9=−3

3−6=−3

The common difference d is -3.

Find the first term : The first term is 12.

Use the formula for the n-th term of an arithmetic sequence:

= +(n−1)d

Plug in =12 and d=−3:

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