These sentences have something to do with ablative of agent but I cannot figure them out.
Quid ab his maleficiis sceleris abesse videtur?
What wrong crimes...???
Erunt etiam altera bella atque iterum ad Troiam magnus mittetur Achilles.
They were
Remember that, in almost all Latin sentences, the subject is usually at the beginning and the main verb is at the end.
In sentence 1, "What" (Quid) is the subject and "seems" (videtur) is the main verb. Everything else will fit after that.
Also in this sentence, there is an infinitive verb form (abesse) to help complete the meaning of the main verb.
Pay attention to phrases. In this sentence, "from" (ab) is a preposition; what noun is its object? What adjectives describe/modify it.
What seems to be missing from these wicked crimes?
Now ... you take sentence 2 apart and let me know what YOU THINK. This one is a little bit different because it starts with a form of "to be" (erunt); when a Latin sentence starts like that, the translation starts with "There were ... "
Let me know ...
There were also the other wars and again Achilles was sent to to the great Troy?
The first sentence, "Quid ab his maleficiis sceleris abesse videtur?" is asking "What seems to be lacking from these crimes of wickedness?" In this sentence, the ablative of agent is "his maleficiis" which means "from these crimes of wickedness." The question is asking what is absent or missing from these crimes.
The second sentence, "Erunt etiam altera bella atque iterum ad Troiam magnus mittetur Achilles." translates to "There will also be another war, and again, great Achilles will be sent to Troy." In this sentence, the ablative of agent is not explicitly present, but it is implied that someone will be sending Achilles to Troy. The sentence implies that Achilles will be sent by an unknown and unmentioned agent.