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2 years ago

Use the distributive property to write an expression equivalent to 15(5+n)

Mathematics

1 answer:

Ratling [72]2 years ago

8 0

The answer is i beleve 75+15n

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Write the expression in the form a+bi<br>(3-5i)(2+2i)

Amanda [17]

$(3-5i)(2+2i)=\\
6+6i-10i+10=\\
16-4i$

5 0

3 years ago

Need help on this! (plz help)

Lynna [10]

Step-by-step explanation:

you just need to put each in the calculator. I'm not so sure what an ALEKS calculator is

5 0

3 years ago

A car and a motor bike are priced at $23440. If the value of the car is four times the value of the motor bike, how much is the

LenKa [72]

x + y = 23440

x = 4y

y = ?

23440 / 5 = 4688

y = $4688

6 0

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

What is the x-coordinate of the red point

Katarina [22]

Well, an x-coordinate is the horizontal line on a grid. The y-coordinate is the vertical line on the grid. You would have to show us the grid to answer that question.

6 0

3 years ago