Show that if an n-vertex graph G contains at least [n/4]+1 edges, then G contains at least [n/2] triangles. 3. Show that if an n-vertex

Show that if an n-vertex graph G contains at least [n²/4]+1 edges, then G contains at least [n/2] triangles.

3. Show that if an n-vertex graph G contains at least L + J +1 edges, then G contains at least L # J triangles.