(2) Apply De Morgan's theorem to the expression (xy)' in example 2.2.3 and simplify the expression. Example 2.2.3: From Table 2.2.2, show xy + (xy)' = 1 Solution: Let e = xy, hence e' = xy and xy + (xy)' = e+e' = 1 (3) Explain in one line, how the equality in example 2.2.3 was obtained from properties of Boolean algebra