Oops. I just noticed I missed a small mistake here.

Originally Posted by
juliie
ohhh ok so it would be
((x)(x' V y')) = (x V x') ∧ (x V y')
((y)(x' V y')) = (y V x')∧ ( y V y')
It should be:
((x)(x' V y')) = (x x') V (x y')
((y)(x' V y')) = (y x') V ( y y')
Be careful!
Now, let's go back to what we have:
((xy)∨(x'y'))' = ((x x') V (x y')) ∨ ((y x') V ( y y'))
You'll need to apply the other law of complementation:
((xy)∨(x'y'))' = ((x x') V (x y')) ∨ ((y x') V ( y y')) = (0 V (x y')) ∨ ((y x') V 0)
Can you do something more with this?