Answer:
D.
Step-by-step explanation:
with questions like this try using Desmos
 
        
                    
             
        
        
        
Answer:
Even if a person doesn't show symptoms, they can still have it.
Step-by-step explanation:
That's the problem. 
Even if you think everyone isn't sick, they very well could be, and because there is no vaccine and it spreads so quickly, there's a chance that all the people in that group could get it.
 
        
                    
             
        
        
        
Answer:
Graph A
Step-by-step explanation:

Its mean graph should intersect x axis at x = 7 and x = - 1. This everything is satisfied by graph A.
 
        
                    
             
        
        
        
Answer:
The domain is the x axis from - 10 to 10 horizontal and the range is the y axis - 10 to 10 vertical