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3 years ago

2x-y=-1 3x-y=2 in simultaneous equations

Mathematics

2 answers:

zloy xaker [14]3 years ago

8 0

Answer:

Let's solve for x.

2x−y=−13x−y

Step 1: Add 13x to both sides.

2x−y+13x=−13x−y+13x

15x−y=−y

Step 2: Add y to both sides.

15x−y+y=−y+y

15x=0

Step 3: Divide both sides by 15.

15x

x=0

Answer:

x=0

Step-by-step explanation:

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GaryK [48]3 years ago

6 0

Answer:

{x,y}={3,7}

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Complete the diamond and submit your answer as a file upload.<br> 9<br> -10

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Answer:

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3 years ago

-1/6*-1/5=<br> pls help fast I will give brainliest to first or second

spin [16.1K]

Answer:

Step-by-step explanation:

-1/6 * -1/5 = 1/30

A negative number times a negative number equals a positive number. When multiplying fractions, the numerators get multiplied over the denominators being multiplied. so -1 * -1 = 1 which is the numerator. 6 * 5 is 30 which is the denominator.

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2 years ago

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Find the measure of the exterior angle

EastWind [94]

Answer:

A exterior angle of a polygon is an angle outside the polygon formed by one of its sides and the extension of an adjacent side.

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3 years ago

Assume you have noted the following prices for books and the number of pages that each book contains. Book Pages (x) Price (y) A

belka [17]

Answer:

a) $y=0.00991 x +1.042$

b) $r^2 = 0.7503^2 = 0.563$

c) $r=\frac{7(30095)-(4210)(49)}{\sqrt{[7(2595100) -(4210)^2][7(354) -(49)^2]}}=0.7503$

Step-by-step explanation:

Data given

x: 500, 700, 750, 590 , 540, 650, 480

y: 7.00, 7.50 , 9.00, 6.5, 7.50 , 7.0, 4.50

Part a

We want to create a linear model like this :

$y = mx +b$

Wehre

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

And:

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

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

With these we can find the sums:

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}=2595100-\frac{4210^2}{7}=63085.714$

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i){n}}=30095-\frac{4210*49}{7}=625$

And the slope would be:

$m=\frac{625}{63085.714}=0.00991$

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

$\bar x= \frac{\sum x_i}{n}=\frac{4210}{7}=601.429$

$\bar y= \frac{\sum y_i}{n}=\frac{49}{7}=7$

And we can find the intercept using this:

$b=\bar y -m \bar x=7-(0.00991*601.429)=1.042$

And the line would be:

$y=0.00991 x +1.042$

Part b

The correlation coefficient is given by:

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

For our case we have this:

n=7 $\sum x = 4210, \sum y = 49, \sum xy = 30095, \sum x^2 =2595100, \sum y^2 =354$

$r=\frac{7(30095)-(4210)(49)}{\sqrt{[7(2595100) -(4210)^2][7(354) -(49)^2]}}=0.7503$

The determination coefficient is given by:

$r^2 = 0.7503^2 = 0.563$

Part c

$r=\frac{7(30095)-(4210)(49)}{\sqrt{[7(2595100) -(4210)^2][7(354) -(49)^2]}}=0.7503$

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3 years ago

$900,000 is what percent of $900,000?

USPshnik [31]

What type of question is this

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