Unfriendly Persuasion

 is a quest in Fallout: New Vegas.

Quick walkthrough
Marcus asks you to convince some NCR mercenaries to go away peacefully. With 65 speech you can simply ask them to leave and complete the quest.

If you ask them how much it costs to bribe them they will say 2500caps. You can get the caps from Marcus by asking him. If you then use speech to convince them to leave for free you have just earned a mint. Finally you can just kill them all, this is actually pretty easy considering that they all never move and can easilly be taken out with a silenced scoped weapon from afar for a sneak attack critical. To make it even easier Marcus and a random mutant will come to your aid! In fact they even have enough health to kill them all for you. The downside of course is NCR infamy.

Detailed walkthrough
First after finding Jacobstown Marcus will approach you with news of New California Republic mercenaries harrasing the town. He'll then ask you to peacefully deal with them. When asked why the the mutants don't kill them Marcus says it's to avoid the NCR from having an excuse to terminate Jacobstown.

Finding the mercs is relativelly easy in that they're directly in front of the town. To resolve the quest you can give them 2500 caps or with a 65 Speech test peacefully tell them to leave.

Or if you have no money/speech and are impacient you can kill them all for some really good loot and NCR infamy. There's 4 ways to kill them all.

1. Use a long range suppresed weapon and mines to take them out with sneak attack criticals and explosions.

2. Take them out head on, Anti-materiel rifle with Armor Piercing rounds recommended.(hardest)

3. Attack them then run to Marcus and the other Super mutant and let them kill the mercenaries. (easiet)

4. Do 3. but help Marcus to make sure he dosen't die.

After completin the quest you get good Jacobstown infamy, 350 or so XP, and loot if you killed them.