The difference (-) between 3 times a number (3n) and 21.
3n - 21
        
             
        
        
        
Answer:
A Fraction
Step-by-step explanation:
33/3 is a fraction because it consists of a numerator and a denominator.
 
        
                    
             
        
        
        
Answer:
either 2^8/3^8 or 256/6561
Step-by-step explanation:
looked it up on Symbolab
 
        
             
        
        
        
Let x = liters 20% solution to be added
then
.12(12) + .20x = .14(12+x)
.12(12) + .20x = .14(12+x)
1.44 + .20x = 1.68 + .14x
.20x = .24 + .14x
.06x = .24
x = 4 liters
Hope this helped!!