We have seen that the operators {+, . , } are functionally complete. It is easy to show that {+, } and { . , } are two smaller sets of operators that are functionally complete (by using the same technique as the previous exercise). In this exercise, we will show that the even smaller set {} is complete. is the NOR operator, which means x y = x+y. a) Express x with only x and the operator. b) Express xy with only x, y and the operator. [3 pts] c) Conclude that the set {} is complete. [2 pts] d) Verify it by expressing x+yz using only x, y, z and the operator. [