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valentina_108 [34]
3 years ago
9

Simplify the expression (-2+4i)-(2+7i) I am not great at these--

Mathematics
2 answers:
e-lub [12.9K]3 years ago
8 0

( - 2 + 4i) - (2 + 7i) \\ ( - 2 + 4i) + ( - 2 - 7i) \\  - 2 + ( - 2) =  - 4 \\ 4i + ( - 7i) =  - 3i \\  - 4 - 3i
Gre4nikov [31]3 years ago
3 0
(-2+4i)-(2+7i)
-2+4i+(-2-7i)
Remove ( )
-2+4i+-2-7i
-4+4i-7i
-4-3i Is the answer. Nope this helps.
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Margot could pickle 500 cucumbers in 2 hours. She got tired and reduced her rate by one half. How long would it take her to pick
Mariulka [41]
Margot could pickle 500 cucumbers in 2 hours.
She got tired and reduced her rate by one half.
=> 250 cucumber in 2 hours
Let's solve how long would it take her to pickle 2000 cucumbers at thenew rate.
=> 2000 / 250 = 8 times 2 hours
=> it will take her 16 hours to do so.
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3 years ago
A supervisor must split 60 hours of overtime between five people. One employee must be assigned twice the number of hours as eac
insens350 [35]

Answer:

A. 10 hours for 4 employees and 20 hours for 1 employee.

Step-by-step explanation:

Okay, let's get to it! :D

So first, we need to set up an equation.

We know there are 60 total hours split between 5 people, and we can assign the number of hours 4 of the employees get as x. We also know that one employee gets double the amount of hours, so they would get 2x. Now, let's put that into an equation :)

60 = 2x + 4x

Now we add the x's together so the equation looks like this:

60 = 6x

To find x, we have to get it alone, so now we divide 60 by 6.

X = 10

But we're not done yet. X is the amount the 4 employees have to work, but because one employee has double the hours, we double our x-value to get 20 hours for that one employee.

3 0
3 years ago
mandar is making a congruence statement for the congruent triangles shown find his mistake and correct it
sergeinik [125]
Mandar never wrote anything
4 0
3 years ago
Find the length of the indicated line segment .
zlopas [31]

Answer:

Step-by-step explanation:

Set this up as a proportion

20/8 = 15/vx           Cross multiply

20*vx = 8 * 15

20 * vx = 120          Divide by 20

vx = 6

3 0
3 years ago
A simple random sample of size equals 49 is obtained from a population with mu equals 88 and sigma equals 14. ​(a) Describe the
Gnoma [55]

Answer:

a) \bar X \sim N(88,\frac{14}{\sqrt{49}}=2)  

b) P(\bar X >91.2)=1-P(\bar X

Step-by-step explanation:

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".  

The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".

The central limit theorem states that "if we have a population with mean μ and standard deviation σ and take sufficiently large random samples from the population with replacement, then the distribution of the sample means will be approximately normally distributed. This will hold true regardless of whether the source population is normal or skewed, provided the sample size is sufficiently large".

The complement rule is a theorem that provides a connection between the probability of an event and the probability of the complement of the event. Lat A the event of interest and A' the complement. The rule is defined by: P(A)+P(A') =1

Let X the random variable that represent the variable of interest on this case, and for this case we know the distribution for X is given by:  

X \sim N(\mu=88,\sigma=14)  

And let \bar X represent the sample mean, by the central limit theorem, the distribution for the sample mean is given by:  

\bar X \sim N(\mu,\frac{\sigma}{\sqrt{n}})  

​(a) Describe the sampling distribution of x overbar.

\bar X \sim N(88,\frac{14}{\sqrt{49}}=2)  

(b) What is Upper P (x overbar greater than 91.2 )​

First we can to find the z score for the value of 91.2. And in order to do this we need to apply the formula for the z score given by:

z=\frac{x-\mu}{\frac{\sigma}{\sqrt{n}}}  

If we apply this formula to our probability we got this:  

z=\frac{91.2-88}{\frac{14}{\sqrt{49}}}=1.6

And we want to find this probability:

P(\bar X >91.2)=1-P(\bar X

On this last step we use the complement rule.

3 0
3 years ago
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