Answer:

Step-by-step explanation:
The explicit rule for the arithmetic sequence is given by:
....[1]
where,
is the first term
d is the common difference and n is the number of terms.
Given sequence:
12.5, 11, 9.5, 8, 6.5, 5 ...
This is an arithmetic sequence.
here,
and d =- 1.5
Substitute these in [1] we have;

⇒
⇒
Therefore, the explicit rule for the given sequence is, 