inverting op amp with a load resistor
There are two places where you can put your resistor.
Outside the feedback loop and Inside the feedback loop.

If you place it outside the feedback loop(other terminal of the resistance is not connected to any terminal of the feedback resistance),then it became a part of your load, not the op-amp circuit.So it do not effect your gain.But it will effect your load resistance.

If you place it inside the feedback circuit,then it will become a part of feedback resistance. According to the connection of the other terminal of the resistance , it may act as parallel or series resistance with main feedback resistance and gain will change .Gain will change according to the equivalent resistor of the main feedback resistance and added the new one.