title: Convert this logic sentence to Conjunctive Normal Form
body: <p>I am struggling to convert this sentence to CNF:</p>
  
  <p>(A ∨ B) ⇔ (C ∧ D).</p>
  
  <p>I have already tried to use the Biconditional elimination logic rule to eliminate the ⇔.</p>
  
  <p>(A ∨ B) → (C ∧ D) ∧ (C ∧ D) → (A ∨ B).</p>
  
  <p>Then I eliminated the → with the Implication elimination logic rule. Now I have </p>
  
  <p>¬(A ∨ B) ∨ (C ∧ D) ∧ ¬(C ∧ D) ∨ (A ∨ B).</p>
  
  <p>I am pretty much stuck here. My professor says I should use Distributivity rule to reduce the sentence. I can't seem to find anything that matches the requirements of Distributivity rule. So, I can't seem to use Distributivity rule before doing some logical rule that I do not know of. </p>
  
  <p>What am I missing here? Can Stack Overflow help me to resume the conversion to CNF?</p>