Answer:
   12 hours
Step-by-step explanation:
If we assume that the units of D are kg, then we can put the given number into the equation and solve.
   21 = h +9
   12 = h . . . . . subtract 9
Eli worked 12 hours to prepare 21 kg of dough.
 
        
             
        
        
        
Answer:
17
Step-by-step explanation:
You have to plug -2 into every x in the function, so:
(-2)^2 - 3 (-2) + 7
4 + 6 + 7
17
 
        
             
        
        
        
Answer:
$2450
Step-by-step explanation:
7% of 5000 is 350 which means that she would be paying $350 a year and so if you multiply the amount she pays a year ($350) you would get $2450.
I hope this helps. 
 
        
                    
             
        
        
        
Answer:

Step-by-step explanation:
Simplify the expression and you will get this.
hope this helps