I believe the answer is either 5 or -1.5
4n - 7 = 13
7 - 4n = 13
4(5) - 7 = 13
7 - 4(-1.5) = 13
4(5) - 7 = 13
        
             
        
        
        
Answer:
the speed is 12mph
Step-by-step explanation:
hope this helps :)
 
        
                    
             
        
        
        
X - 6y=18     
2x-3y=9    |*-2
   x -6y=18
-4x+6y=-18
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-3x=0, x=0
2x-3y=9
2*0-3y=9
-3y=9, y=-9/3, y= -3
        
             
        
        
        
Answer:
Well, it's the perimeter, so...40.
You just calculate the perimeter of a rectangle with the lenght of 12 and width of 8, by the formula 

or you can factor it out.
 
        
             
        
        
        
Answer:
Step-by-step explanation:
volume=9×3×4+6×3×4+3×3×4=(9+6+3)×3×4=18×12=216 yd³