The net force on an object is the sum of all the individual forces acting on it.
If two opposing forces act on an object, the net force is the difference between the two forces.
When two forces act in the same direction on an object, the net force is the sum of the two forces.
Here the two force 3N and 3N acting on same direction, so
net force = 3N + 3N
= 6N
Forces that are balanced are those that are opposite in direction and equal in size, but here the equal forces acts in same direction so it is unbalanced