title: Simplifying Boolean Expressions with DeMorgan’s law
body: <p>I need help simplifying the following Boolean expressions using DeMorgan’s law:</p>
  
  <p>a) <code>[ (AB)' + (CD)' ]'</code></p>
  
  <p>and</p>
  
  <p>b) <code>[(X+Y)' + (X+Y') ]'</code></p>
  
  <p>Please show some steps so I can do the other ones myself</p>