The first sentence has 2 mistakes. It should be: "However much your services are worth to the company, that's how much the company will pay you." The second sentence contains a reduced relative clause. Without the reduction it would be : "His mother inherited a business which was worth 15,000 dollars a year." "are" and "were" are the verbs which go with "worth", and this, in turn, is used as an adjective.

It is an adjective in both sentences. The first sentence should be, "How much are your services worth to the company..." Are is the verb and worth is an adjective describing the word services.

How much are your services worth to the company. Does the company see your services valuable. The company wants to make money. If your services can help the company make money, then your services are worth a lot. If your services do not help the company make money, then your services are not worth very much. The second sentence indicates an actual monetary value. I bought the antique table for $500, but it is really worth $725. Worth as a verb is no longer used.