If you are able to exert 200 pounds of force against an object but you are only exerting 50 pounds of force to do so, what method are you applying to make this happen?

Using a lever on an object allows you to exert more force upon the object than the amount of force you're actually exerting against the lever itself. In other words, you might rig a lever that can lift a 250 pound boulder but requires only 50 pounds of force against the lever itself.