# how to prove a simple graph with this question [duplicate]

) Suppose G is a simple graph with n vertices. Prove that G has twice as many edges as vertices only if n ≥ 5. ?

Any one can help?

Rephrased: prove that if $n < 5$, $G$ has fewer than $2n$ edges.
Which simple graph on $n$ vertices has the most edges? How many does it have, as a function of $n$?