1. (A v ¬A) & B = (A + ¬A) * B = 1 * B = B;
2. A & (A v B) & (C v ¬B) = A * (A + B) * (C + ¬B) = A * (C + ¬B) = A & (C v ¬B)
3. A & ¬B v B & C v ¬A & ¬B = A * ¬B + B * C + ¬A * ¬B = A * ¬B + ¬A * ¬B + B * C =
= ¬B * (A + ¬A) + B * C = ¬B * 1 + B * C = ¬B + B * C = ¬B + C = ¬B v C
4. A v ¬A & B = A + ¬A * B = A + B = A v B