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Find the sum of the geometric sequence –3, 15, –75, 375, … when there are 7 terms and select the correct answer below.
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Find the sum of the geometric sequence –3, 15, –75, 375, … when there are 7 terms and select the correct answer below.

User Shamnad P S
by
8.2k points

1 Answer

7 votes
-3, 15, -75, 375,…
×5 ×5 ×5

aⁿ = a₁rⁿ⁻¹
aⁿ = 3(5)ⁿ⁻¹

a₅ = -1875
a₆ = 9375
a₇ = -46875
User Alexandr Sulimov
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8.8k points
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