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Find the 9th term of 3 -15 75

1 Answer

8 votes

Answer:

a₉ = 1171875

Explanation:

There is a common ratio r between consecutive terms

r = - 15 ÷ 3 = 75 ÷ = 15 = - 5

This indicates the sequence is geometric with n th term


a_(n) = a₁
r^(n-1)

where a₁ is the first term and r the common ratio

Here a₁ = 3 and r = - 5, then

a₉ = 3 ×
(-5)^(8)

= 3 × 390625

= 1171875

User Steven Evers
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