Answer:
Solution: x = 135
Step-by-step explanation:
Hi there!
First, let´s write the equation:
√(x + 9) /4 = 3
Multiply by 4 both sides of the equation
√(x + 9) = 12
square both sides of the equation
x + 9 = 144
subtract 9 to both sides of the equation
x = 135
Let´s check the solution:
√(x + 9) /4 = 3
x = 135
√(135 + 9) /4 = 3
√(144) /4 = 3
12/4 = 3
3 = 3
Then, x = 135 is the solution to the equation.
Have a nice day!
This are similar answers to your questions.
Congruent to angle 1: 3, 5, 10, 8, and 6
congruent to angle 2: 4, 9, and 7
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 