Question

2/10
if the first term of an arithmetic sequence is 12,
what is the formula for the nth term?
12 - 7(n-1)
12 + 7(n-1)
12 + 7n
12 - 7n

Explanation:

Step1: Recall arithmetic sequence formula

The general formula for the nth term of an arithmetic sequence is $a_n = a_1 + d(n-1)$, where $a_1$ is the first term, and $d$ is the common difference.

Step2: Substitute given first term

We know $a_1 = 12$. Since the common difference $d$ is not explicitly stated, but the standard form matching the options uses the structure with $(n-1)$. The only option that follows the correct general form with the given first term is the one that retains the $(n-1)$ structure, assuming a positive common difference of 7 (the only consistent option with the standard formula).

Answer:

B. 12 + 7(n-1)