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baherus [9]
3 years ago
11

Help, please! Struggling!

Mathematics
1 answer:
MArishka [77]3 years ago
6 0

Answer:

65

Step-by-step explanation:

(4-7i)(4+7i) =16 + 28i-28i -49i^2 ➡16 - 49i^2

16 + 49 = 65

the fault here is i^2= -1 and -1 multiplied by -49 is +49 not -49

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. A study of one thousand teens found that the number of hours they spend on social networking sites each week is normally distr
Gnesinka [82]

We are given the following data:

Sample Size = n = 1000

Sample Mean = u = 15 hours

Population Standard Deviation = s = 2 hours

Since we know the population standard deviation, we can use z distribution to find the confidence interval about the mean. z value for 95% confidence interval is 1.96.

Formula for the confidence interval is:

(u-z\frac{s}{\sqrt{n}} ,  u+z\frac{s}{\sqrt{n}})

Using the values in the formula, we get:

(15-1.96\cdot\frac{2}{\sqrt{1000}},  15+1.96\cdot\frac{2}{\sqrt{1000}})\\ \\  (14.88,15.12)

Therefore, the 95% confidence interval about the population mean is 14.88 hours to 15.12 hours. So B option is the correct answer.

4 0
3 years ago
Read 2 more answers
How do I do this I need help right now
kodGreya [7K]
To answer this (specifically the first one) you have to count how many spaces each point moves. (How many spaces up/down does it go? Left/right?) then you put rise (up/down) over run (left/right) and you should get the slope!
6 0
3 years ago
the mass of mars is approximately 100000000000000000000000 kilograms and that of neptune is about 100000000000000000000000000 ki
rusak2 [61]
Mars-10^23
Neptune-10^26
4 0
3 years ago
Does anyone know the step by step for this 9(m +5) - 3(m - 2) = 8m + 31
tigry1 [53]
<h3>Answer :</h3>

<u>Given</u> :

  • 9(m + 5) - 3(m - 2) = 8m + 31

We have to find value of m.

➠ 9(m + 5) - 3(m - 2) = 8m + 31

➠ 9m + 45 - 3m + 6 = 8m + 31

➠ 9m - 3m + 45 + 6 = 8m + 31

➠ 6m + 51 = 8m + 31

➠ 51 - 31 = 8m - 6m

➠ 20 = 2m

➠ m = 20/2

➠<u> m = 10</u>

<h3>Hope It Helps!</h3>

6 0
3 years ago
Read 2 more answers
The cost for the raw materials of marble countertops, can be represented by the function , where is the area of the countertops.
Lady_Fox [76]

Answer:

m(c(a)) = 4.8875a

Step-by-step explanation:

The missing parameters are:

c(a) = 4.25a --- Cost of marble countertops

m(c) = 1.15c --- Cost of retail markup

Required

The cost of marked up price

This implies that we calculate m(c(a))

We have:

c(a) = 4.25a

m(c) = 1.15c

m(c) = 1.15c can be written as:

m(c(a)) = 1.15*c(a)

Substitute: c(a) = 4.25a

m(c(a)) = 1.15*4.25a

m(c(a)) = 4.8875a

Hence, the cost of marked up price is: m(c(a)) = 4.8875a

5 0
3 years ago
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