1. Is the following distributive law valid or invalid? Provide your answer. Hint: use a truth table to get the answer for each side of the equation. Check whether they are the same or not.

x XOR (y + z) = (x XOR y) + (x XOR z)

2. Draw the logic diagram of a 2-bit encoder, a circuit with four input lines, exactly one of which is high at any instant, and two output lines whose 2-bit binary value tells which input is high.

3. Why have multicore chips suddenly appeared? Are there technological factors that have paved the way? Does Moores law play a role here?