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3 years ago

12x−5y=−20 y=x+4

2 answers:

8 0

12x-5y=-20
y=x+4
Subtract x to each side
y-x=x+4-x
y-x=4
-x+y=4
Multiply -12 to each side
-12(-x+y)=4(-12)
12x-12y=-48
Use substitute property:
12x-12y=-48
-
12x-5y=-20
=
-7y=-28
Divided -7 to each side
-7y/-7=-28/-7
y=4
y=x+4
Substitute y with 4
4=x+4
Subtract both side by 4
4-4=x+4-4
x=0. As a result, the solution to these equations is (0,4). Hope it help!

Alborosie3 years ago

7 0

X = 0
y = 4
(0 , 4) as an ordered pair

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gtnhenbr [62]

Answer:

a) $r=\frac{4(333)-(200)(5.37)}{\sqrt{[4(12000) -(200)^2][4(9.3501) -(5.37)^2]}}=0.9857$

The correlation coefficient for this case is very near to 1 so then we can ensure that we have linear correlation between the two variables

b) $m=\frac{64.5}{2000}=0.03225$

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

$\bar x= \frac{\sum x_i}{n}=\frac{200}{4}=50$

$\bar y= \frac{\sum y_i}{n}=\frac{5.37}{4}=1.3425$

$b=\bar y -m \bar x=1.3425-(0.03225*50)=-0.27$

So the line would be given by:

$y=0.3225 x -0.27$

Step-by-step explanation:

Part a

The correlation coeffcient is given by 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=4 $\sum x = 200, \sum y = 5.37, \sum xy = 333, \sum x^2 =12000, \sum y^2 =9.3501$

$r=\frac{4(333)-(200)(5.37)}{\sqrt{[4(12000) -(200)^2][4(9.3501) -(5.37)^2]}}=0.9857$

The correlation coefficient for this case is very near to 1 so then we can ensure that we have linear correlation between the two variables

Part b

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

Where:

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

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

With these we can find the sums:

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}=12000-\frac{200^2}{4}=2000$

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i){n}}=333-\frac{200*5.37}{4}=64.5$

And the slope would be:

$m=\frac{64.5}{2000}=0.03225$

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

$\bar x= \frac{\sum x_i}{n}=\frac{200}{4}=50$

$\bar y= \frac{\sum y_i}{n}=\frac{5.37}{4}=1.3425$

And we can find the intercept using this:

$b=\bar y -m \bar x=1.3425-(0.03225*50)=-0.27$

So the line would be given by:

$y=0.3225 x -0.27$

4 0

3 years ago

Which expression is equivalent to 4(-3h+2) - (h-8) ???

Lera25 [3.4K]

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3 years ago

translate the sentence into an equation. the product of 8 and a number increased by 4 is 60.a. 8y 4 = 60b. 4y 8 = 56c. 8 ÷ y 4 =

krok68 [10]

Hello,

"T<span>he product of 8 and a number increased by 4" may be understood by 2 ways:
1) it is the number which is increased
2) it is the product which is increased.

1) 8*(y+4) =8y+32

2) (8y)+4=8y+4

Seeing answers
:answer A: 8y+4

</span>

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3 years ago

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podryga [215]

Answer:

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Step-by-step explanation:

call the missing number x

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8-8 - x = -5-8 Combine

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3 years ago

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Diano4ka-milaya [45]

Answer:

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Step-by-step explanation:

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3 years ago

​ ​ ​ ​​ ​12x−5y=−20 ​y=x+4 ​​

12x−5y=−20 y=x+4