What is the common difference in the following arithmetic sequence? n 1 2 3 4 A sub n negative 12 negative 1 10 21

Subtract consecutive terms to find the common difference: −1 − (−12) = 11. The next differences are 10 − (−1) = 11 and 21 − 10 = 11, so the common difference is 11, choice A.

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