1. True :
Take a Triangle graph, with edge weights $2,3,6$. Now add $1$ to all the edges.
2 : True :
Take a Triangle graph, with edge weights $2,3,6$. Now add $1$ to all the edges.
3. True :
Take a Triangle graph, with edge weights $4,5,8$. Now add $-1$ to all the edges.
4. True :
Take a Triangle graph, with edge weights $4,5,8$. Now add $-1$ to all the edges.