Exam Lookup

Which one of the following is NOT a valid identity?




Solution
B. (x + y) ⨁ z = x ⨁ (y + z)



Explanation

 (a) x  y = (xy + x′y ′)′

= (xy )′

= x  y, it is valid.

(b) 

= Σm(1, 2, 4, 6)

= Σm(1, 2, 3, 4)

(x + y)  z ≠ x  (y + z)

So option (b) is invalid.

(c) (x  y)  z = x  (y  z)

Associativity is true on Ex-OR operator so it valid.

(d) 

= (x + y), so it is valid.