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Sphinxa [80]
3 years ago
5

What is the sum of the first 7 terms of the geometric series: -8 + (-4) + (-2) + 1 + 1/2+...

Mathematics
1 answer:
s2008m [1.1K]3 years ago
4 0
a_1=-8;\ a_2=-4;\ r=a_2:a_1\to r=-4:(-8)=\dfrac{1}{2};\ n=7\\\\S_n=\dfrac{a_1(1-r^n)}{1-r}\\\\subtitute:\\\\S_7=\dfrac{-8\left[1-\left(\dfrac{1}{2}\right)^7\right]}{1-\dfrac{1}{2}}=\dfrac{-8\left(1-\dfrac{1}{128}\right)}{\dfrac{1}{2}}\\\\=\dfrac{-8\cdot\dfrac{127}{128}}{\dfrac{1}{2}}=-\dfrac{127}{16}\cdot\dfrac{2}{1}=-\dfrac{127}{8}=-15\dfrac{7}{8}
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Kellogg's produced 715000 boxes of cornflakes this year. This was 110% of annual production last year. What was last year's annu
Charra [1.4K]
Let last year product be x boxes.

110% of x means \displaystyle{  \frac{110}{100}\cdot x.

Thus, we solve the equation:

                                  \displaystyle{ \frac{110}{100}\cdot x=715,000.

Multiplying both sides by  \displaystyle{ \frac{100}{110}, we have:

                    \displaystyle{ x=715,000 \cdot \frac{100}{110}=650,000.


Answer: Last <span>year's annual production was 650,000 boxes.</span>
6 0
3 years ago
What is located at (–2, –2)?
tatuchka [14]

Answer:

B. The post office

youre welcome!

5 0
3 years ago
PLEASE HELP ASAP <br> SHOW WORK pls
Studentka2010 [4]

Answer:

Requires approximately 129 buckets

Step-by-step explanation:

Volume of the tank=200x77x32

Volume of the paint bucket = πr^{2} x h= π x 8 x 8 x 19

(200x77x32) ÷( π x 8 x 8 x 19)= 492800/‭3,820.177=128.999

3 0
2 years ago
Do anyone know what these mean...
a_sh-v [17]

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8 0
3 years ago
– 72 = 3(- 4x – 8)<br> Need help
Finger [1]

Answer:

x = 4

Step-by-step explanation:

Step 1: Write equation

-72 = 3(-4x - 8)

Step 2: Solve for <em>x</em>

<u>Distribute 3:</u> -72 = -12x - 24

<u>Add 24 to both sides:</u> -48 = -12x

<u>Divide both sides by -12:</u> x = 4

Step 3: Check

<em>Plug in x to verify if it's a solution.</em>

-72 = 3(-4(4) - 8)

-72 = 3(-16 - 8)

-72 = 3(-24)

-72 = -72

8 0
3 years ago
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