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3 years ago

Tìm x biết rằng 2x - 4 = 5

Mathematics

2 answers:

LenaWriter [7]3 years ago

6 0

Answer:

The answer is $\frac{9}{2}$

Step-by-step explanation:

$2x-4=5\\2x=5+4\\x=\frac{9}{2}$

Dmitrij [34]3 years ago

5 0

Answer:

start by adding 4 to the other side. Now you have 2x=9. Now in order to get x by itself you divide and get x=9/2.

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Is y = -x a proportional relationship

Karo-lina-s [1.5K]

Answer:

For any proportional relationship, k=yx (such as a line that passes through the origin). Find the equation of the line by solving for y in the constant of proportionality equation. This equation y=kx is another representation of a proportional relationship.

Step-by-step explanation:

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3 years ago

Read 2 more answers

Question: Solve the system of equations. Show or explain your reasoning.

Dovator [93]

The answer is x=2, y= -1

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2 years ago

An experiment was conducted to evaluate the success of an Ebola virus vaccine. The subjects were unaware of the treatment they w

Irina-Kira [14]

Answer:

your answer would be

B complexity

I agree that it is B but would suggest that you also consider the implications of each answer. They are all technically correct.

A is correct simply due to the fact that the longer time passes without an ebola cure, the more people can be potentially infected with it, resulting in less healthy individuals that may be able to volunteer to test potential ebola vaccines. Scientists need healthy volunteers from affected regions in order for rapid clinical trials to occur.

B is correct because of the nature of epidemics. A combination of technical, social, economic, and geographical obstacles slow the progress and dissemination of ebola vaccine information.

C is correct because finance impacts everything from finding resources used in studying ebola to distributing vaccines to affected areas. Economic imbalances or money shortages negatively impact research.

D is correct due to many social factors (more of a subjective answer). Some people think that vaccine distributors discriminate against certain ethnic groups. Others think the governments/other organizations are not effective enough at managing the situation. Still others feel that the search for a cure is not being approached in the right way. In all, there are multiple ways to oppose different aspects of ebola research.

Ultimately, B is correct because it seems to capture the meaning of A, C, and D together.

6 0

3 years ago

Find the average of 2, 6, 12, 8, and 7

Crazy boy [7]

Answer:

Step-by-step explanation:

7 0

3 years ago

a survey amony freshman at a certain university revealed that the number of hours spent studying the week before final exams was

Marat540 [252]

Answer:

Probability that the average time spent studying for the sample was between 29 and 30 hours studying is 0.0321.

Step-by-step explanation:

We are given that the number of hours spent studying the week before final exams was normally distributed with mean 25 and standard deviation 15.

A sample of 36 students was selected.

Let $\bar X$ = sample average time spent studying

The z-score probability distribution for sample mean is given by;

Z = $\frac{ \bar X-\mu}{\frac{\sigma}{\sqrt{n} } }} }$ ~ N(0,1)

where, $\mu$ = population mean hours spent studying = 25 hours

$\sigma$ = standard deviation = 15 hours

n = sample of students = 36

The Z-score measures how many standard deviations the measure is away from the mean. After finding the Z-score, we look at the z-score table and find the p-value (area) associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X.

Now, Probability that the average time spent studying for the sample was between 29 and 30 hours studying is given by = P(29 hours < $\bar X$ < 30 hours)

P(29 hours < $\bar X$ < 30 hours) = P( $\bar X$ < 30 hours) - P( $\bar X$ $\leq$ 29 hours)

P( $\bar X$ < 30 hours) = P( $\frac{ \bar X-\mu}{\frac{\sigma}{\sqrt{n} } }} }$ < $\frac{ 30-25}{\frac{15}{\sqrt{36} } }} }$ ) = P(Z < 2) = 0.97725

P( $\bar X$ $\leq$ 29 hours) = P( $\frac{ \bar X-\mu}{\frac{\sigma}{\sqrt{n} } }} }$ $\leq$ $\frac{ 29-25}{\frac{15}{\sqrt{36} } }} }$ ) = P(Z $\leq$ 1.60) = 0.94520

So, in the z table the P(Z $\leq$ x) or P(Z < x) is given. So, the above probability is calculated by looking at the value of x = 2 and x = 1.60 in the z table which has an area of 0.97725 and 0.94520 respectively.

Therefore, P(29 hours < $\bar X$ < 30 hours) = 0.97725 - 0.94520 = 0.0321

Hence, the probability that the average time spent studying for the sample was between 29 and 30 hours studying is 0.0321.

7 0

3 years ago