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Yuri [45]
2 years ago
7

Please teach me on how to answer this question. (addmath question)

Mathematics
1 answer:
arsen [322]2 years ago
5 0

We know that \overline{x}=8 so:

\overline{x}=8\\\\\\\dfrac{\sum\limits_{k=1}^7\,x_k}{7}=8\qquad|\cdot7\\\\\\ \boxed{\sum\limits_{k=1}^7\,x_k=56}

We want to calculate:

\sum\limits_{k=1}^7\,\big(2x_k-3\big)^2=\sum\limits_{k=1}^7\,\big(4x_k^2-12x_k+9\big)=\\\\\\=\sum\limits_{k=1}^7\,4x_k^2-\sum\limits_{k=1}^7\,\big12x_k+\sum\limits_{k=1}^7\,9=4\sum\limits_{k=1}^7\,x_k^2-12\sum\limits_{k=1}^7\,x_k+\sum\limits_{k=1}^7\,9=\\\\\\=4\cdot672-12\cdot56+7\cdot9=2688-672+63=\boxed{2079}

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A n =−1+3(n−1) an=−1+3(n−1) what is the 55 term in the sequence
Sindrei [870]
ANSWER

a_{55}=161


EXPLANATION

The general term for the sequence is


a_n=-1+3(n-1)


To find the 55th term, we have to substitute
n = 55
in to the general term and simplify.



This implies that,

a_{55}=-1+3(55-1)



a_{55}=-1+3(54)




a_{55}=-1+162



a_{55}=161


Therefore the 55th term is 161.
8 0
2 years ago
Malachai is doing a 20 miles bike ride. He has cycled 11 miles so far. What percentage of the the total distance has he cycled
Anestetic [448]
11 miles / 20 miles =.55
.55 x 100 = 55%
11/20 is the proportion and you multiply by 100 to gey a percent
another way to solve is
11/20 x 5/5 = 55/100 = 55%
you multiply by 5/5 because it is equal to one and it makes the denominator equal to 100 it also follows the rule that whatever you do to the top you must do with the bottom
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3 years ago
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Jet001 [13]
The second one, 21.4666.
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3 years ago
Find the Perimeter of the<br> rectangle using the formula.<br> 4.2<br> 6.7<br> · Perimeter = 2L + 2W
Anon25 [30]

Answer:

21.8

Step-by-step explanation:

2(4.2)+2(6.7)=8.4+13.4=21.8

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2 years ago
Cheek your level in mathematics
Naily [24]

sorry...

Step-by-step explanation:

I need some points...

8 0
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