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2 years ago

HELP I WILL GIVE BRAINLIEST

Mathematics

2 answers:

Lubov Fominskaja [6]2 years ago

8 0

Answer:

A. x= -3

Step-by-step explanation:

firstly collect all the terms . then move the term so it'd look like 5x+14 = -2x - 7 then calculate it then it would look like this : 5x+2x = -7 -14 after you move the terms you again calculate it and then the finish product would look like this : 7x = -21 so after you get that you divide by both sides and the answer is -3 . (im sorry if that don't make sense) but the answer is A.

AysviL [449]2 years ago

3 0

Answer:

The letter "x" is often used in algebra to mean a value that is not yet known. It is called a "variable" or sometimes an "unknown". In x + 2 = 7, x is a variable, but we can work out its value if we try! A variable doesn't have to be "x", it could be "y", "w" or any letter, name or symbol.

X COULD BE 2 OR 7

Step-by-step explanation:

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А)

Nookie1986 [14]

Answer:

Step-by-step explanation:

surface area of sphere=a

4pir^2=a

r^2=a/4p

r=root(a/4pi)

if radius is doubled

r1=2root(a/4pi)

r1^2=4(a/4pi)

a/a1=(4pia/4pi)/(4pi 4a/4pi)=1/4

so a is increased by 4 times

6 0

2 years ago

Sulfur compounds cause "off-odors" in wine, so winemakers want to know the odor threshold, the lowest concentration of a compoun

aev [14]

Answer:

a) $29.4-1.96\frac{7}{\sqrt{10}}=25.06$

$29.4+1.96\frac{7}{\sqrt{10}}=33.74$

So on this case the 95% confidence interval would be given by (25.06;33.74)

b) $z=\frac{29,4-25}{\frac{7}{\sqrt{10}}}=1.988$

$p_v =P(z>1.988)=0.0234$

If we compare the p value and the significance level given $\alpha=Step-by-step explanation:Previous conceptsA confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval". 
The margin of error is the range of values below and above the sample statistic in a confidence interval. 
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean". 
Part a
Data given: 30 30 42 35 22 33 31 29 19 23
We can calculate the sample mean with the following formula:[tex] \bar X = \frac{\sum_{i=1}^n X_i}{n}= 29.4$ the sample mean

$\mu$ population mean (variable of interest)

$\sigma=7$ represent the population standard deviation

n=10 represent the sample size

95% confidence interval

The confidence interval for the mean is given by the following formula:

$\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (1)

Since the Confidence is 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.025,0,1)".And we see that $z_{\alpha/2}=1.96$

Now we have everything in order to replace into formula (1):

$29.4-1.96\frac{7}{\sqrt{10}}=25.06$

$29.4+1.96\frac{7}{\sqrt{10}}=33.74$

So on this case the 95% confidence interval would be given by (25.06;33.74)

Part b

What are H0 and Ha for this study?

Null hypothesis: $\mu \leq 25$

Alternative hypothesis : $\mu>25$

Compute the test statistic

The statistic for this case is given by:

$z=\frac{\bar X-\mu_o}{\frac{\sigma}{\sqrt{n}}}$ (1)

z-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".

We can replace in formula (1) the info given like this:

$z=\frac{29,4-25}{\frac{7}{\sqrt{10}}}=1.988$

Give the appropriate conclusion for the test

Since is a one side right tailed test the p value would be:

$p_v =P(z>1.988)=0.0234$

Conclusion

If we compare the p value and the significance level given $\alpha=0.05$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis.

8 0

2 years ago

PLEASE PLEASE HELP ME ASAP

Vika [28.1K]

Answer: DC=30.5

Step-by-step explanation:

Use trigonometry to solve this question

sin=O/H
cos=A/H
tan=O/A

----------------------------------------------------------

First Step: find BD

- AB relative to 54° is [hypotenues]

- BD relative to 54° is [opposite]

- Therefore, we need to use O/H, which is Sin

- sin(54°)=O/20=20·sin(54°)=16.2

Second Step: Find DC

- DC relative to 28° is [adjacent]

- BD relative to 28° is [opposite]

- Therefore, we need to use O/A, which is tan

- tan(28°)=16.2/A=16.2/tan(28°)=30.5

Hope this helps!! :)

Please let me know if you have any questions

4 0

2 years ago

A group of preschoolers has 30 boys and 13 girls what is the ratio of boys to all children?

vekshin1

A group of preschoolers has 30 boys and 13 girls then the ratio of boys to all children would be 30:43.

What is a ratio?

A ratio in mathematics shows how many times one number contains another. For example, if a bowl of fruit contains eight oranges and six lemons, the orange-to-lemon ratio is eight to six. Similarly, the lemon-to-orange ratio is 6:8, and the orange-to-total fruit ratio is 8:14.

A group of preschoolers has 30 boys and 13 girls.

Total children will be = 30 + 13 = 43

Ratio = number of boys/total children

= 30/43.

Hence, if A group of preschoolers has 30 boys and 13 girls then the ratio of boys to all children would be 30:43.

To learn more about the ratio, visit:

brainly.com/question/12024093

#SPJ1

7 0

10 months ago

Cosx = 1/2<br>tan X = 0 solve

Reil [10]