Answer:
If the shape of end face has n sides
Then, in total, there are n+2 faces 
Using that formula
Faces in 20-sided polygon = n+2 = 20+2 = 22
Step-by-step explanation:
Pls vote as brainliest 
 
        
             
        
        
        
You know 1 is not a root because the sum of the coeffcients of the equation is 14, not zero.
It is fairly easy to try 3 by synthetic division (see attachment), which tells you that 3 is a root and the remaining quadratic factor is x²-3x-5. The quadratic formula tells you the roots of that factor are 
... x = (-b±√(b²-4ac))/(2a) = (3±√29)/2
The appropriate choices are
... C. (3-√29)/2
... D. (3+√29)/2
... F. 3
_____
The quadratic formula tells you the solution to
... ax²+bx+c=0
is x = (-b±√(b²-4ac))/(2a)
We have a=1, b=-3, c=-5.
 
        
             
        
        
        
First, you factor and simplify (respectively) the numerator and denominator. Your equation becomes:

Notice, there is a (x + 7) on both the top and the bottom. Because of this, they cancel each other out. What is left is your answer:
 
 
        
        
        
Y = -x^2 + x + 2
y = -x + 3
-x + 3 = -x^2 + x + 2
x^2 - x - 2 - x + 3 = 0
x^2 -2x + 1 = 0
(x - 1)(x - 1) = 0
x - 1 = 0      y = -x + 3
x = 1           y = -1 + 3
                   y = 2
solutions are : (1,2) , (1,2)
        
                    
             
        
        
        
Step-by-step explanation:
[ Refer to the attachment ]
-  Q 1 was not clear but yet !!