Multiple choice

Find the (n - 1)th term of the given sequence. 7, 14, 21, 28, ...

  1. 14n

  2. 7n

  3. 7n - 1

  4. 7n - 7
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D Correct answer
Explanation

The sequence is 7, 14, 21, 28... which is 7n. The (n-1)th term is 7(n-1) = 7n - 7.

AI explanation

Observe that the given sequence is an arithmetic progression with the first term as 7 and a common difference of 7. The nth term formula for an arithmetic progression is a + (n - 1)d, so substituting the values gives 7 + (n - 1)7, which simplifies to 7n. To find the (n - 1)th term, replace n with (n - 1) to get 7(n - 1), which expands to 7n - 7. The result is 7n - 7.

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