3 if 5 times a number plus two is 17, then we can say 5x+2=17 if we subtract two on each side we have 5x=15, divide each side by 5 and you get x=3 so your answer is 3
see the attached figure to better understand the problem
we have that
![cos(A)=\frac{1}{5} \\ AB=12\ units\\ CD=2\ units](https://tex.z-dn.net/?f=cos%28A%29%3D%5Cfrac%7B1%7D%7B5%7D%20%5C%5C%20AB%3D12%5C%20units%5C%5C%20CD%3D2%5C%20units)
Step 1
<u>Find the value of AC</u>
we know that
in the right triangle ABC
![cos (A)=(AC/AB)\\AC=AB*cos(A)](https://tex.z-dn.net/?f=cos%20%28A%29%3D%28AC%2FAB%29%5C%5CAC%3DAB%2Acos%28A%29)
substitute the values in the formula
![AC=12*(1/5)\\ AC=2.4\ units](https://tex.z-dn.net/?f=AC%3D12%2A%281%2F5%29%5C%5C%20AC%3D2.4%5C%20units)
Step 2
<u>Find the value of BC</u>
we know that
in the right triangle ABC
Applying the Pythagorean Theorem
![AB^{2} =AC^{2}+BC^{2}\\ BC^{2}=AB^{2} -AC^{2}](https://tex.z-dn.net/?f=AB%5E%7B2%7D%20%3DAC%5E%7B2%7D%2BBC%5E%7B2%7D%5C%5C%20BC%5E%7B2%7D%3DAB%5E%7B2%7D%20-AC%5E%7B2%7D)
substitute the values
![BC^{2}=12^{2} -2.4^{2}\\BC^{2}= 138.24\\ BC=11.76\ units](https://tex.z-dn.net/?f=BC%5E%7B2%7D%3D12%5E%7B2%7D%20-2.4%5E%7B2%7D%5C%5CBC%5E%7B2%7D%3D%20138.24%5C%5C%20BC%3D11.76%5C%20units)
Step 3
<u>Find the value of BD</u>
we know that
in the right triangle BCD
Applying the Pythagorean Theorem
![BD^{2} =DC^{2}+BC^{2}](https://tex.z-dn.net/?f=BD%5E%7B2%7D%20%3DDC%5E%7B2%7D%2BBC%5E%7B2%7D)
substitute the values
![BD^{2} =2^{2}+11.76^{2}](https://tex.z-dn.net/?f=BD%5E%7B2%7D%20%3D2%5E%7B2%7D%2B11.76%5E%7B2%7D)
![BD=11.93\ units](https://tex.z-dn.net/?f=BD%3D11.93%5C%20units)
therefore
<u>the answer is</u>
the length of BD is 11.93 units
Answer:
3x + 3y
Step-by-step explanation:
The two minus signs make a plus sign. Therefore, we replace the minus signs with a plus sign, getting 3x + 3y.
Answer:
n=1849
Step-by-step explanation:
Previous concepts
A 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".
The population proportion have the following distribution
Solution to the problem
In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 99% of confidence, our significance level would be given by
and
. And the critical value would be given by:
The margin of error for the proportion interval is given by this formula:
(a)
And on this case we have that
and we are interested in order to find the value of n, if we solve n from equation (a) we got:
(b)
Assuming that the proportion is estimated
. And replacing into equation (b) the values from part a we got:
And rounded up we have that n=1849