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What is the value of the 11th term in the following geometric sequence?

-5, -10, -20, -40

-5,120
-100
-180
-19,531,250

User Vikoo
by
4.3k points

1 Answer

4 votes

Answer:

-5,120

Explanation:

The first term (a1) of this sequence is -5. The common ratio (r) is -10/-5 = 2. So, the general formula for the n-th term tells you ...

an = -5·2^(n-1)

Putting 11 where n is in the formula, we find the 11th term to be ...

a11 = -5·2^(11 -1) = -5·1024 = -5,120

The 11th term in the sequence is -5,120.

User Steviethecat
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4.1k points