40 points: Implement, using only AND, OR and NOT gates, a circuit with two inputs, A and B, and one output X. X should be 1 if and only if A and B have the same value. Don't use NAND, NOR, XOR, or NXOR.

40 points: Implement A XOR B as a circuit using only one AND, one OR, and one NAND gate.

10 points: Implement A OR B using only NOR gates.