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2 years ago

Need help asap!!!!!!!!!

Mathematics

2 answers:

UNO [17]2 years ago

6 0

9514 1404 393

Answer:

3420

Step-by-step explanation:

The first term is 20. The common ratio is -40/20 = -2. Fill these values into the formula and evaluate.

$S_9=\dfrac{20-20\cdot(-2)^9}{1-(-2)}=\dfrac{20-20(-512)}{3}=\dfrac{10260}{3}\\\\ \boxed{S_9=3420}$

tatuchka [14]2 years ago

5 0

Answer:

Step-by-step explanation:

In general, a geometric sequence is given by:

In the sequence 20, - 40 , 80,…

First term, a1 = 20

Common ratio, r = - 40 ÷ 20 = - 2

The nth term is = 9th

Sum of finite geometric series : Sn= ( a1 - a1r^n ) / ( 1 - r)

S9 = ( 20 - 20 x (- 2)^9 ) / ( 1 - ( - 2) )

S9 = ( 20 - 20 x - 512 ) / ( 1 + 2 )

S9 = ( 20 - 10240<em> </em>) / ( 3 )

S9 = ( - 10220 ) / 3

<h3>S9 = - 3400 <u>Answer</u> </h3><h2>Hope it's help you.... ^_^❤️</h2>

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Answer:

I understand there is a typo, so Belly and Billy are the same person. His age is represented as B, and Suzy's as S.

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Step-by-step explanation:

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Answer:

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Step-by-step explanation:

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