¬ (P ↔ Q)

2.Graphs: Is the statement “For every natural number n ≥ 1 there exists a directed graphof n vertices for which every vertex has an indegree equal to its outdegree” TRUE or FALSE?

3.Strings and Languages: For alphabet Σ = {a, b, c}, suppose x ∈ Σ∗ and |x| = 5. Give astring x0that is a substring of x and has the following property:Among all substrings of x, x0is both a prefix of x and a suffix of x, and is the longest substringof x.