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# Which sequences are arithmetic? check all that apply. –8.6, –5.0, –1.4, 2.2, 5.8, … 2, –2.2, 2.42, –2.662, 2.9282, … 5, 1, –3, –7, –11, … –3, 3, 9, 15, 21, … –6.2, –3.1, –1.55, –0.775, –0.3875, …

Blair Lewis

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#### 1 answer

Ramon Kelly on November 24, 2018

In an arithmetic sequence, the next term is found by adding a constant term to each number to get to the next number. The common difference can be found by subtracting the first term from the second term.-8.6, -5.0, -1.4, 2.2, 5.8....the common difference here is 3.6-8.6 + 3.6 = -5.0-5.0 + 3.6 = -1.41.4 + 3.6 = 2.22.2 + 3.6 = 5.8 so this IS an arithmetic progression.2,-2.2, 2.42, -2.662, 2.9282...there is no common difference..so this is not an arithmetic sequence5,1,-3,-7,-11....common difference is -45 + (-4) = 11 + (-4) = -3-3 + (-4) = -7-7 + (-4) = -11this IS an arithmetic sequence-3,3,9,15,21...common difference is 6-3 + 6 = 33 + 6 = 99 + 6 = 1515 + 6 = 21this IS an arithmetic progression-6.2, -3.1, -1.55, -0.775, -0.3875...this is not an arithmetic progression