Mathematics
DeneenNeiford
17

find an explicit rule for the nth term of the sequence. 7, 21, 63, 189, ... select one: a. an = 7 • 3n b. an = 7 • 3n - 1 c. an = 3 • 7n - 1 d. an = 7 • 3n 1

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(1) Answers
iza90290

If you look at by making a guess. a = 7*3ⁿ,    n = 0, 1, 2, 3,.... Test: when n = 0,   a = 7*3⁰ = 7 * 1 = 7 when n = 1,   a = 7*3¹ = 7 * 3 = 21 when n = 2,   a = 7*3² = 7 * 9 = 63 when n = 3,   a = 7*3³ = 7 * 27 = 189 So  a = 7*3ⁿ,    n = 0, 1, 2, 3,....

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