passive...

[nautes20]

Dear teacher...

I heard that "This problem was not answered by nobody."
I don't know the reason.

Best regards... :D

[Casiopea]

Dear teacher...

I heard that "This problem was not answered by nobody."
I don't know the reason.

Best regards... :D

Active: Nobody answered the problem. (OK)
Passive: The problem was not answered. (OK)
Passive: The problem was not answered by nobody. (Not OK)

not...nobody is a double negative.

[nautes20]

Dear Casiopea...

The question is : I was answered by nobody.

Best regards... :D

[Casiopea]

Dear Casiopea...

The question is : I was answered by nobody.

Best regards... :D

You've lost me.

[nautes20]

The questio is : The problem was solved by nobody."

[Casiopea]

The question is : The problem was solved by nobody."

The problem was solved. (OK)
The problem was solved by nobody. (Not OK; According to the affirmative verb 'was solved', someone acted out the action, and yet according to the semantic subject, 'nobody', the someone who acted out the action doesn't exist.

Someone solved it.
It was solved (affirmative) by someone.

Nobody solve it.
It wasn't solved (negative) by anyone.

Nobody didn't solve it. (Not OK; Double Negative)
It wasn't solved by nobody. (Not OK; Double negative)

You can't negate the subject (i.e., nobody) to express negation on the verb (i.e., not solve). Verbs and subjects are different animals. They have their own rules.

[nautes20]

a clear answer! Thanks....

[Casiopea]

a clear answer! Thanks....

You're welcome. :D