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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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3 years ago

1. Determine whether line KM and line ST are Parallel, Pers

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Answer:

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Step-by-step explanation:

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Slope of ST = $-\frac{8}{5}$

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We can use the slope of a line to determine whether they are perpendicular or parallel to one another.

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2 years ago

Places A and B are 100km apart from each other on a highway. A car starts from A and another from B at the same time. If they mo

Mashutka [201]

Answer:

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Step-by-step explanation:

The calculation of speeds of the cars is given below:-

Assume that the speed of the 1st car which is opening from A = x km/hr

and assume the Speed of the 2nd car which is starting from B

= y km/hr

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Time = Distance ÷ Speed

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80km d = 80 km

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Time = 1 hr 20 minutes

That means

= (1 + 20 ÷ 60) hr

= (80 ÷ 60)

= 4/3 hr

d = 80km

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3 years ago

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To find the rate in miles per hour, divide the miles by the hours.
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3 years ago

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