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4 years ago

7

Create three different expressions that are each equal to 20. Each expression should include only these three numbers: 4, -2, an

d 10.

1 answer:

Archy [21]4 years ago

3 0

Answer:

Step-by-step explanation:

you could do;

10 x -2 = 20

-2 x (-2) x 10 divided by (-2) + 10 + 10 + 10 +10 =20

4 + 4 - 10 x -2 - 4 - 4 = 20

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"Select the equation of the least squares line for the data: (34.0, 1.30), (32.5, 3.25), (35.0, .65), (31.0, 6.50), (30.0, 5.85)

yulyashka [42]

Answer:

$y=-1.055 x +37.643$

And the best option would be:

a. ŷ= 37.643-1.0543x

Step-by-step explanation:

We assume that the data is this one:

x: 34.0, 32.5, 35.0, 31.0, 30.0, 27.5, 29.0

y: 1.30, 3.25, 0.65, 6.50, 5.85, 8.45, 6.50

Find the least-squares line appropriate for this data.

For this case we need to calculate the slope with the following formula:

$m=\frac{S_{xy}}{S_{xx}}$

Where:

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i)}{n}$

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}$

So we can find the sums like this:

$\sum_{i=1}^n x_i = 34.0+ 32.5+ 35.0+ 31.0+ 30.0+ 27.5+ 29.0
=219$

$\sum_{i=1}^n y_i =1.3+3.25+0.65+6.5+5.85+8.45+6.5=32.5$

$\sum_{i=1}^n x^2_i = 34.0^2+ 32.5^2+ 35.0^2+ 31.0^2+ 30.0^2+ 27.5^2+ 29.0^2
=6895.5$

$\sum_{i=1}^n y^2_i =1.3^2+3.25^2+0.65^2+6.5^2+5.85^2+8.45^2+6.5^2=202.8$

$\sum_{i=1}^n x_i y_i =34*1.3 + 32.5*3.25+ 35*0.65+ 31*6.5+30*5.585 +27.5*8.45 +29*6.5=970.45$

With these we can find the sums:

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}=6895.5-\frac{219^2}{7}=43.929$

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i)}{n}=970.45-\frac{219*32.5}{7}=-46.336$

And the slope would be:

$m=-\frac{46.336}{43.929}=-1.055$

Nowe we can find the means for x and y like this:

$\bar x= \frac{\sum x_i}{n}=\frac{219}{7}=31.286$

$\bar y= \frac{\sum y_i}{n}=\frac{32.5}{7}=4.643$

And we can find the intercept using this:

$b=\bar y -m \bar x=4.643-(-1.055*31.286)=37.643$

So the line would be given by:

$y=-1.055 x +37.643$

And the best option would be:

a. ŷ= 37.643-1.0543x

5 0

4 years ago

Please answer in the 2nd photo is the vocabulary you have to use you do not have to use all of the vocabulary.

o-na [289]

Answer:

It would take 69 days for the sunflower to grow 6 feet. I know this because I found the unit rate by dividing 92 by 8 which equals 11.5. Since it is a proportional relationship all i had to do was times 11.5 by 6 to get the ratio 6 feet per 69 days.

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3 years ago

In a certain region of the country, the proportion of the population with blue eyes is currently 17 percent. A random sample of

lana66690 [7]

Answer:

0.17

Step-by-step explanation:

The mean of a random sample is equal to the mean of the population.

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4 years ago

The product of 2x^2+6x-8 and x+3 in standard form

anzhelika [568]

Answer:

2x³ + 12x² + 10x - 24

Step-by-step explanation:

(2x² + 6x - 8)(x + 3) Distribute

2x³ + 6x² + 6x² + 18x - 8x - 24 Combine like terms

2x³ + 12x² + 10x - 24 This expression is in standard form

If this answer is correct, please make me Brainliest!

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4 years ago

Find the Total Surface Area and the Volume of these shapes:

fiasKO [112]

Answer:

6156

Step-by-step explanation:

formula is TSA=2LW+2LH+2HW

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3 years ago