mathematical expression of third law of Newton?

The third law of Newton states that for every action, there is an equal and opposite reaction. This can be expressed mathematically as:

F1 = -F2

where F1 is the force exerted by object 1 on object 2, and F2 is the force exerted by object 2 on object 1. The negative sign indicates that the forces are equal in magnitude but opposite in direction.