Sunday 18 March 2012

Introduction to Algebra

x + 5 = 12

Start with: x + 5 = 12
   
What you are aiming for is an answer like "x = ...", and the plus 5 is in the way of that!
If you subtract 5 you can cancel out the plus 5 (because 5-5=0)
 
   
So, let us have a go at subtracting 5 from both sides: x+5 -5 = 12 -5
   
A little arithmetic (5-5 = 0 and 12-5 = 7) becomes: x+0 = 7
   
Which is just: x = 7
  Solved!
(Quick Check: 7+5=12)  

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