title: Exclusive OR Associativity Boolean Algebra Proof
body: <p>Prove <code>(A ⊕ B) ⊕ C = A ⊕ (B ⊕ C)</code> using boolean algebra.
  I made the truth tables and found the sum of products, but couldnt figure how to show their equal.</p>
  
  <p>I then tried doing  </p>
  
  <pre><code>(a xor b) xor c  (a' - is NOT(A)/inverse)
  (a'b + ab') ⊕ C
  c' (a'b + ab') + c[(a'b + ab')']  
  </code></pre>
  
  <p>Couldn't go from there, </p>