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24 votes
24 votes
Use the sequence below to complete each task. 3, -15, 75, ... a. Identify the common ratio (r). b. Write an equation to represent the sequence. C. Find the 5th term (as) Algebra), 2013 → B I y Default A A : = 5 川里

User Tnotstar
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1 Answer

18 votes
18 votes

a)

This is a geometric sequence, this means that each value of the sequence is multiplied by the common ratio to determine the next number.

For the sequence {3,-15,75}

Divide one of the given numbers by the number before it on the sequence to determine the common ratio


r=(-15)/(3)=-5

The common ratio for this sequence is r=-5

b)

a is the first value of the sequence

r is the common ratio

k is the place on the sequence of the required value

You can calculate said value using


ar^k

c)

For

a=3

r=-5

k=5

The value fo the sequence is


ar^k=3(-5)^5=-9375

User Kiril  Mytsykov
by
3.0k points
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