If and, then verify that

(A + B)’ = A’ + B’,

(A+B)’ = A’+B’

Explanation: We will first calculate L.H.S i.e. (A+B)’ and then consecutively we will calculate R.H.S and verify that both are equal.

Therefore,

Now,

So,

From equation 1 & 2 we verify that

(A+B)’ = A’+B’. Hence verified.