It is called a fact Family
        
             
        
        
        
The domain of a function is the set of input or argument values for which the function is real and defined.
So, for the given function to be defined, we need to find the possible values for which the values of x makes the square root to be positive.
That is;
-9 -5x ≥ 0
Now, let's solve for x
Add 9 to both-side of the equation
-5x ≥ 9
Divide both-side by -5
x ≤ -9/5
Therefore, the domain of the function can be represented in interval notation as: ( - ∞ , -9/5]
 
 
        
             
        
        
        
You have not given us any of the steps that Ricardo took to simplify the 
expression, and you also haven't given us the list of choices that includes 
the description of his mistake, so you're batting O for two so far.  
Other than those minor details, the question is intriguing, and it certainly 
draws me in.
If Ricardo made a mistake in simplifying that expression, I'm going to say that
it was most likely in the process of removing the parentheses in the middle.  
Now you understand that this is all guess-work, because of all the stuff that you 
left out when you copied the question, but I think he probably forgot that the  3x  
operates on everything inside the parentheses.
He probably wrote that  3x (x-3)  is
either    3x² - 3
     or       x - 9x .
In reality, when properly simplified,
       3x (x - 3)  =  3x² - 9x .
        
             
        
        
        
Answer: 
30
Step-by-step explanation:
x = 7
( x - 4 )^2 + 3x
= ( 7 - 4 )^2 + 3 ( 7 )
= 3^2 + 21
= 9 + 21
= 30 
 
        
                    
             
        
        
        
Total numbers=10
mean(average)=14.8
standard deviation=3.4254
variance_standard deviation)=11.73333
population standard deviation=3.24962
variance(population standard deviation)=10.56