Answer:
x = 71/8
Step-by-step explanation:
Solve for x:
5 X (8 x - 71) = 0
Divide both sides by 5 X:
8 x - 71 = 0
Add 71 to both sides:
8 x = 71
Divide both sides by 8:
Answer:  x = 71/8
 
        
             
        
        
        
Answer: Rearrange:
Rearrange the equation by subtracting what is to the right of the equal sign from both sides of the equation : 
 4*x+2*x+1-(2*x-x+21)=0 
Step by step solution :
STEP
1
:
Pulling out like terms
 1.1 Pull out like factors :
 5x - 20 = 5 • (x - 4) 
Equation at the end of step
1
:
STEP
2
:
Equations which are never true:
 2.1 Solve : 5 = 0
This equation has no solution.
A a non-zero constant never equals zero.
Solving a Single Variable Equation:
 2.2 Solve : x-4 = 0 
 Add 4 to both sides of the equation : 
 x = 4 
One solution was found :
 x = 4
 
        
             
        
        
        
Answer:
To complete the square, we need to have the equation set up like this:
x^2 +4x =9
To do that, we'd need to move the 4x to the left side producing
4x + x^2 = 9
And that can be rewritten as 
x^2 +4x =9
So the term that needs to be moved is -4x
https://www.1728.org/quadr2.htm
Step-by-step explanation:
 
        
             
        
        
        
Looks like the PMF is supposed to be

which is kinda weird, but it's not entirely clear what you meant...
Anyway, assuming the PMF above, for this to be a valid PMF, we need the probabilities of all events to sum to 1:

Next,





If 

, then 

, where we take the positive root because we know 

 can only take on positive values, namely 1, 2, and 5. Correspondingly, we know that 

 can take on the values 

, 

, and 

. At these values of 

, we would have the same probability as we did for the respective value of 

. That is,

Part (5) is incomplete, so I'll stop here.
 
        
        
        
Where you stop/finish. hope that helps :)