SOLUTION: what would a two column proof look like for the problem 7x+8=3x+28

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Question 529823: what would a two column proof look like for the problem 7x+8=3x+28
Answer by Edwin McCravy(20056)   (Show Source): You can put this solution on YOUR website!
       7x+8 = 3x+28                        Given

[7x+8]+(-8) = [3x+28]+(-8)                 Adding (-8) to both sides

7x+[8+(-8)] = 3x+[28+(-8)]                 Associative principle of addition

     7x + 0 = 3x+[28+(-8)]                 Inverse principle of assition
   
         7x = 3x+[28+(-8)]                 Identity principle of addition

         7x = 3x+20                        Performing addition

   7x+(-3x) = [3x+20]+(-3x)                Adding (-3x) to both sides.        

   7x+(-3x) = 3x+[20+(-3x)]                Associative principle of addition

   7x+(-3x) = 3x+[(-3x)+20]                Commutative principle of addition

   7x+(-3x) = [3x+(-3x)]+20                Associative principle of addition

   7x+(-3x) = 0 + 20                       Inverse principle of addition
                
   7x+(-3x) = 20                           Identity principle of addition

x[7 + (-3)] = 20                           Distributive principle  

       x(4) = 20                           Performing addition

   [x(4)]· = 20·                         Multiplying both sides by 

   x[(4)·] = 20·                         Associative principle of multiplication

       x[1] = 20·                        Inverse principle of multiplication

          x = 20·                        Identity principle of multiplication

          x = 5                           Performing multiplication 

Edwin
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