Newton's first law - "Everybody remains in a state of rest or constant velocity unless acted on by a force"
If the forces are balanced then the object will continue at a constant velocity. If the forces are unbalanced then the object will accelerate in the direction of the net force.
Newton's second law - "the force applied to an object is directly proportional to the acceleration of the object"
Force = mass x acceleration
Newton's third law - "every action has an equal but opposite reaction"