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3 years ago

Evaluate B^2 for a B = 9 • 18 •81 •92

Mathematics

1 answer:

BaLLatris [955]3 years ago

5 0

Answer:

Step-by-step explanation:

if b is 9 cubed you would just multiply 9 ×9 and get 81

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notka56 [123]

Answer:

Step-by-step explanation:

She added 3x and -2x, getting 5x, instead of x. She needs to pay more attention to the positive/negative signs.

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2 years ago

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Strike441 [17]

Answer:

1/6 + 1/2 = 1/6 + 3/6 = 4/6

SIMPLIFIED IS = 2/3

Step-by-step explanation:

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2 years ago

The number of motor vehicles registered in millions in the US has grown as follows:

zysi [14]

Answer:

a) Figure attached

b) $r=\frac{n(\sum xy)-(\sum x)(\sum y)}{\sqrt{[n\sum x^2 -(\sum x)^2][n\sum y^2 -(\sum y)^2]}}$

For our case we have this:

n=10 $\sum x = 75.819, \sum y = 43.5231, \sum xy = 330.0321, \sum x^2 =574.8598, \sum y^2 =192.8274$

$r=\frac{10(330.0321)-(75.81948)(43.5231)}{\sqrt{[10(574.8598) -(75.819)^2][10(192.8274) -(43.5231)^2]}}=0.989$

So then the correlation coefficient would be r =0.989

Step-by-step explanation:

Previous concepts

The correlation coefficient is a "statistical measure that calculates the strength of the relationship between the relative movements of two variables". It's denoted by r and its always between -1 and 1.

Solution to the problem

Part a

Year (x): 1940, 1945 1950, 1955, 1960, 1965, 1970, 1975, 1980, 1985

Vehicles (Y): 32.4, 31.0, 49.2, 62.7, 73.9, 90.4, 108.4, 132.9, 155.8, 171.7

After apply natural log for the two variables and create the scatterplot in excel we got the following result on the figure attached.

Part b

And in order to calculate the correlation coefficient we can use this formula:

$r=\frac{n(\sum xy)-(\sum x)(\sum y)}{\sqrt{[n\sum x^2 -(\sum x)^2][n\sum y^2 -(\sum y)^2]}}$

For our case we have this:

n=10 $\sum x = 75.819, \sum y = 43.5231, \sum xy = 330.0321, \sum x^2 =574.8598, \sum y^2 =192.8274$

$r=\frac{10(330.0321)-(75.81948)(43.5231)}{\sqrt{[10(574.8598) -(75.81948)^2][10(192.8274) -(43.5231)^2]}}=0.989$

So then the correlation coefficient would be r =0.989

4 0

2 years ago

In 2009, the world's largest pumpkin weighed 784 kilograms. An average-sized pumpkin weighs 5,000 grams. The 2009 world-record p

denpristay [2]

First you need to convert grams into kilograms. You know that 1kg=1000g
if 1kg=................. 1000g
x kg=.................5000g

x=5000/1000 = 5kg
Now you need to find the difference between an average-sized pumpkin and the <span>world's largest pumpkin which is:
784-5=779

So the right answer is 779.</span>

5 0

3 years ago

What is the value of x for the regular polygon shown below?<br> 2x + 4<br> 36

Elden [556K]

Im not sure what your asking add more please

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1 year ago