Use truth tables to prove each of the following Boolean identities. Doing this is easy.
Construct the truth table for the left hand side. Then construct the truth table for the right hand side. If the final column of both tables is the same then the two expressions have the same truth values. In that case, we say that they are equivalent.
a. A ∨ B = B ∨ A
b. ¬(A ∨ B) = ¬A ∧ ¬B (one of De Morgan's laws)