if the resultant of all forces acting on a body is zero in the case of balanced forces,then why it is said that the forces acting on a lift moving downwards with uniform motion are balanced?

For a lift moving downwards with uniform motion, acceleration is zero.

Force = mass x acceleration

So, force is also zero.

If an object has zero acceleration we must conclude that there is no resultant force acting on it.

So a lift moves with uniform motion even if the forces acting on it are balanced.