Multiple choice

What is the 12th term of the sequence -1, 2, 7, 14,...?

  1. 144

  2. 142

  3. 140

  4. 138
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Sequence: -1, 2, 7, 14. Differences: 3, 5, 7. This is an arithmetic progression of differences. The n-th term is n^2 - 2. Check: 1^2-2 = -1, 2^2-2 = 2, 3^2-2 = 7, 4^2-2 = 14. 12th term = 12^2 - 2 = 144 - 2 = 142.

AI explanation

The differences between consecutive terms increase by 2, as seen in the changes from 3 to 5 to 7, making the general formula n^2 minus 2. For the 12th term, substitute 12 into the formula to get 12 squared minus 2. This gives 144 minus 2, resulting in 142.

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