If delta g (is that what you mean) is on the left and minus, it means that the reaction has to give away energy in order to occur.
It will not require energy (at this level of study. later on you will learn that it will require energy to get started).
The reaction will yield energy.
I think you are intended to say it will occur spontaneously. That is 1/2 true. There is however an activation energy, which you can google.
Both of the last two require a knowledge of activation energies. The reaction will occur if the activation energy is overcome.
