First, you can factor them into (x-8)(x+9)=0 then set x-8=0 and x+9=0, in which you get X = 8 or X = -9
        
             
        
        
        
Yes.
70% of the customers buy a coffee drink and 30% buy food.
The sum of it is 100% already.
So 20% of it just another addition of information since it cannot exceed 100% of percentage (100% + 20% = 120%).
It also contains a subset for both percentage.
 
        
                    
             
        
        
        
So the function we're dealing with is
f(x) = 

Factorising we get, 

 Therefore, the vertical asymptotes are at x = 3 and x = 6
Therefore, the vertical asymptotes are at x = 3 and x = 6