1.He invented a business plan which companies can employ (to earn profits.)
I bracketed the part which I think is the purpose adjunct,
the understood subject of the infinitive is companies, right?
can the relative clause be viewed as:
Companies can employ the business plan to earn profits?
2.He is asked to investigate [what the police believe to be the root of the crime] (to discover the truth.)
The first infinitive to be the root of the crime,
the understood subject is relative pronoun what,right?
Can the noun phrase be viewed as:
The police believe what to be the root of the crime?
The second infinitive to discover the truth is a purpose adjunct,
and the understood subject is he?