If you could solve all these and note when you use a theorem

(e) Y= (A + B + C)D + AD + B (f) Y = ABCD + ABCD + (B + D)(AB C) 3. Hard: Y-ABCD+ ABC+ ABCD + ABD + ABCD +BCD+A (b) Y-ABD + AD + AB + (A + B + CD(A +)) (c) Y-ABC + (A +)(B + D) (d) Y = (AB + CC + (A + B)(C + D))(ABCD + AD(AC + BOD + BD + ABD) 4. Extra Hard