All categories

4 years ago

Solve for all values of x (x+9)2=4

Mathematics

2 answers:

serg [7]4 years ago

7 0

Answer:

x = -7

Step-by-step explanation:

you have to distribute the 2 to what is in the parenthesis, then you get left with 2x+18=4 so subtract the 18 from both sides leaving you with 2x=-14 so you divide both by 2 leaving you with x=-7.

andreyandreev [35.5K]4 years ago

4 0

Answer:

x= -7

Step-by-step explanation:

You might be interested in

A teacher surveys a sample of students from Lake Middle School. He asks the students where they’d like to go for a field trip. H

hichkok12 [17]

Answer: 210/1000

Step-by-step explanation:

80+ 60+30+40= 210/100

8 0

3 years ago

Please need help thank

babunello [35]

Answer:

Step-by-step explanation:

If each amount of time is a separate person, then 7

6 0

3 years ago

Read 2 more answers

A die is rolled 50 times with the following results:

mote1985 [20]

Answer:

Zero.

Step-by-step explanation:

The empirical (or experimental ) probability is that calculated from the result of the trial.

There were no 5's thrown so the empirical probability of a 5 coming up is 0/50 or 0.

7 0

3 years ago

an item is purchased for a wholesale price of $48 and will be sold at a 55 percent markup. which expression should be used to fi

Reil [10]

48 times 1.55 equals 74.4.

7 0

3 years ago

Read 2 more answers

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

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

4 0

3 years ago