4. Simplify each of the following expressions using DeMorgan's theorems.

(a) ABC (b) ABCD (c) AB (d) A(B+C)D

a) ABC

ABC = AC B = (AC) + B

=A+C+B

6) ABCD

c) To =

d) A(B+5) 0

AB + (20) = Ã+B+CD

(A+B) = AB

At

=

AD. (B+C)

= AD + (3+2)

= A + 0 + 8 +0