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andriy [413]
3 years ago
6

Which of the following is a solution of x2 + 2x + 4?

Mathematics
1 answer:
ivolga24 [154]3 years ago
3 0
Strictly speaking, x^2 + 2x + 4 doesn't have solutions; if you want solutions, you must equate <span>x^2 + 2x + 4 to zero:

</span>x^2 + 2x + 4= 0.  "Completing the square" seems to be the easiest way to go here:

rewrite   x^2 + 2x + 4  as   x^2 + 2x + 1^2 - 1^2 = -4, or
                                              (x+1)^2 = -3
or                                            x+1 =i*(plus or minus sqrt(3))

or                                            x = -1 plus or minus i*sqrt(3)

This problem, like any other quadratic equation, has two roots.  Note that the fourth possible answer constitutes one part of the two part solution found above.
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Expand the brackets 3(12-W)
3241004551 [841]

Answer:

36 - 3m

Step-by-step explanation:

3(12−m)

3 \times 12+3(−m)

36+3(−m)

36−3m

<h3>Hope it is helpful...</h3>
8 0
3 years ago
It would be enchanting if you could help me out on this question, pease and crackers. thank you!(don't mind my weird language lo
Alina [70]

Answer:

615.44cm

Step by Step Answer:

A=πr^{2}=π·14^{2}≈615.75216

5 0
3 years ago
Assume that the paired data came from a population that is normally distributed. using a 0.05 significance level and dequalsxmin
Artemon [7]
"<span>Assume that the paired data came from a population that is normally distributed. Using a 0.05 significance level and d = (x - y), find \bar{d}, s_{d}, the t-test statistic, and the critical values to test the claim that \mu_{d} = 0"

You did not attach the data, therefore I can give you the general explanation on how to find the values required and an example of a random paired data.

For the example, please refer to the attached picture.

A) Find </span><span>\bar{d}
You are asked to find the mean difference between the two variables, which is given by the formula:
\bar{d} =  \frac{\sum (x - y)}{n}

These are the steps to follow:
1) compute for each pair the difference d = (x - y)
2) sum all the differences
3) divide the sum by the number of pairs (n)

In our example: 
</span><span>\bar{d} =  \frac{6}{8} = 0.75</span>

B) Find <span>s_{d}
</span><span>You are asked to find the standard deviation, which is given by the formula:
</span>s_{d} =  \sqrt{ \frac{\sum(d - \bar{d}) }{n-1} }

These are the steps to follow:
1) Subtract the mean difference from each pair's difference 
2) square the differences found
3) sum the squares
4) divide by the degree of freedom DF = n - 1

In our example:
s_{d} = \sqrt{ \frac{101.5}{8-1} }
= √14.5
= 3.81

C) Find the t-test statistic.
You are asked to calculate the t-value for your statistics, which is given by the formula:
t =  \frac{(\bar{x} - \bar{y}) - \mu_{d} }{SE}

where SE = standard error is given by the formula:
SE =  \frac{ s_{d} }{ \sqrt{n} }

These are the steps to follow:
1) calculate the standard error (divide the standard deviation by the number of pairs)
2) calculate the mean value of x (sum all the values of x and then divide by the number of pairs)
3) calculate the mean value of y (sum all the values of y and then divide by the number of pairs)
4) subtract the mean y value from the mean x value
5) from this difference, subtract  \mu_{d}
6) divide by the standard error

In our example:
SE = 3.81 / √8
      = 1.346

The problem gives us <span>\mu_{d} = 0, therefore:
t = [(9.75 - 9) - 0] / 1.346</span>
  = 0.56

D) Find t_{\alpha / 2}
You are asked to find what is the t-value for a 0.05 significance level.

In order to do so, you need to look at a t-table distribution for DF = 7 and A = 0.05 (see second picture attached).

We find <span>t_{\alpha / 2} = 1.895</span>

Since our t-value is less than <span>t_{\alpha / 2}</span> we can reject our null hypothesis!!

7 0
3 years ago
The average of four numbers is 98. If three of those numbers are 86, 87, and 91, what is the fourth number?
BabaBlast [244]

Answer:

128

Step-by-step explanation:

86 plus 87 plus 91 =264  

You have to get 98 times 4 which is 392  

Then;

392-264, which is 128, which is the answer (the fourth number)  

So;

86+87+91+128 = 392 divided by 4 (the number of numbers there is) which equals 98!  

Hope it helped

Please mark me as Brainliest

4 0
4 years ago
Read 2 more answers
Ellen rotated triangle ABC 90° clockwise around point A to form triangle ACD and rotated triangle ABC 180° clockwise around poin
Serjik [45]
It is a. You didnt load the pic but if you did if you rotated Dc 90 it would complete BE. 
6 0
3 years ago
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