Answer:
 x = 9.0
Step-by-step explanation:
 
        
             
        
        
        
Step-by-step explanation:
4x+9y=28
-4x-y=-28
8y=0 
divide both side by 8 
y=0
solve for X in equation 1
4(X)-9(0)=28
4x-0=28
4x =28 
divide both side by 4
4x/4=28/4
X= 7
y=0,x=7
 
        
             
        
        
        
Answer:
 what grade is this
Step-by-step explanation:
 
        
             
        
        
        
The answer is choice D:
exponents are listed from highest to lowest.