Answer:
C
Step-by-step explanation:
3x=1x+5
ummm are the red circles a plus or minus ??
Answer:
Where
and 
Since the distribution for X is normal then the distribution for the sample mean is also normal and given by:



So then is appropiate use the normal distribution to find the probabilities for 
Step-by-step explanation:
Previous concepts
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 letter
is used to denote the cumulative area for a b quantile on the normal standard distribution, or in other words: 
Solution to the problem
Let X the random variable that represent the variable of interest of a population, and for this case we know the distribution for X is given by:
Where
and 
Since the distribution for X is normal then the distribution for the sample mean
is also normal and given by:



So then is appropiate use the normal distribution to find the probabilities for 
Well the answer i got was

when i multiplied
the answer i got when i added was
Answer:
Simplify
![Q-[R+S]-T](https://tex.z-dn.net/?f=Q-%5BR%2BS%5D-T)
The answer is:

Step-by-step explanation:
We have the expressions:

Now, we need simplify:
![Q-[R+S]-T](https://tex.z-dn.net/?f=Q-%5BR%2BS%5D-T)
We need to replace each term by the expressions:
![7m+3n-[(11-2m)+(n+5)]-(-m-3n+8)](https://tex.z-dn.net/?f=7m%2B3n-%5B%2811-2m%29%2B%28n%2B5%29%5D-%28-m-3n%2B8%29)
We need to remember the rule of signs:



With this in mind we solve the parentheses:
![7m+3n-[(11-2m)+(n+5)]-(-m-3n+8)](https://tex.z-dn.net/?f=7m%2B3n-%5B%2811-2m%29%2B%28n%2B5%29%5D-%28-m-3n%2B8%29)
![7m+3n-[11-2m+n+5]+m+3n-8](https://tex.z-dn.net/?f=7m%2B3n-%5B11-2m%2Bn%2B5%5D%2Bm%2B3n-8)

let's group common terms

We must add and subtract common terms:

The answer is:
