Final answer:
The given expression does not align with the context provided, and so without further information or correction, an accurate answer cannot be given.
Step-by-step explanation:
The expression 345xy + 78yd + 4567xyd - 4532y² does not seem to make sense in the context provided, nor does it relate to any physical quantity like μN which stands for micronewtons, a unit of force. The question appears to contain typos or misunderstandings. Without the proper context or correct expression, it's impossible to provide an accurate answer to this problem. If this notation represents some physical formula or calculation, please provide additional details or correct the expression so that we may assist you further.