Question

Which answer is the explicit rule for the sequence 12.5, 11, 9.5, 8, 6.5, 5 ... ?

Answer 1

Which answer is the explicit rule for the sequence ?
Answer:
12.5, 11, 9.5, 8, 6.5, 5, ...
4. an = 14 − 1.5n

Hope this helps ;)

Answer 2

Answer:

$a_n = 14-1.5n$

Step-by-step explanation:

The explicit rule for the arithmetic sequence is given by:

$a_n =a_1+(n-1)d$          ....[1]

where,

$a_1$ 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, $a_1=12.5$  and d =- 1.5

Substitute these in [1] we have;

$a_n = 12.5+(n-1)(-1.5)$

⇒$a_n = 12.5-1.5n+1.5$

⇒$a_n = 14-1.5n$

Therefore, the explicit rule for the given sequence is, $a_n = 14-1.5n$