Question

find a pattern for the sequence below. use the pattern to find the next three terms.
24, 21, 18, 15, 12, _

Explanation:

Step1: Find the common - difference

Subtract consecutive terms: $21 - 24=- 3$, $18 - 21=-3$, $15 - 18=-3$, $12 - 15=-3$. The common - difference $d=-3$.

Step2: Calculate the next term

To find the next term, add the common - difference to the last given term. Let the last given term $a_n = 12$ and $d=-3$. Then the next term $a_{n + 1}=a_n + d$. So $a_{n+1}=12+( - 3)=9$.

Answer:

9