Банк принял заявление о несогласии.

Because the subject is банк (bank), which is a masculine singular noun in Russian.

In the past tense, Russian verbs agree with the subject in gender and number:

• принял = masculine singular
• приняла = feminine singular
• приняло = neuter singular
• приняли = plural

So:

• Банк принял... = The bank accepted...
• If the subject were компания, you would say Компания приняла...

Yes, заявление is in the accusative, but for many inanimate neuter nouns, the nominative and accusative forms are identical.

So:

• nominative: заявление
• accusative: заявление

That means the form does not visibly change, even though the grammatical case does.

This is very common in Russian. For example:

• Я вижу письмо.
• Он подписал заявление.

Both письмо and заявление are neuter inanimate nouns, so nominative and accusative look the same.

О несогласии is in the prepositional case because of the preposition о, which often means about / concerning and normally requires the prepositional.

Here:

• о = about / concerning
• несогласии = prepositional singular of несогласие

So заявление о несогласии literally means something like a statement/application about disagreement/objection.

More examples:

• книга о России = a book about Russia
• разговор о работе = a conversation about work

Because after о, the noun usually goes into the prepositional case.

The base form is:

• несогласие = disagreement / objection / lack of consent

Its prepositional singular form is:

• о несогласии

This follows a common neuter-noun pattern:

• здание → о здании
• решение → о решении
• несогласие → о несогласии

So the ending changes from -е to -и.

Grammatically, it is a noun phrase made up of:

• заявление = statement, application, declaration, notice
• о несогласии = about disagreement / objection / non-acceptance

In official or legal contexts, заявление о несогласии often means something like:

• a statement of disagreement
• an objection
• a notice of dispute
• a formal declaration that someone disagrees

The exact English wording depends on context, but the Russian structure is straightforward: a statement/application concerning disagreement.

Normally, no — заявление о несогласии is the natural construction.

Russian often uses о + prepositional after nouns like заявление, сообщение, доклад, книга, when the meaning is about / concerning.

So:

• заявление о несогласии = a statement about disagreement

Without о, the relationship between the two nouns changes, and заявление несогласия would sound unnatural or at least much less standard in this context.

Yes. Just like English, Russian can use institutions, companies, and organizations as grammatical subjects.

So банк принял заявление means literally the bank accepted the application/statement, even though in real life an employee acted on behalf of the bank.

This is very normal official style. Similar examples:

• Суд принял решение. = The court made a decision.
• Компания отправила письмо. = The company sent a letter.

Принял is perfective.

The verb pair is:

• принимать = imperfective
• принять = perfective

Here, the perfective is used because the sentence describes a completed action: the bank accepted the statement.

Compare:

• Банк принимал заявления. = The bank was accepting statements / used to accept statements.
• Банк принял заявление. = The bank accepted the statement.

So the perfective focuses on the result: the acceptance happened.

Russian has no articles like the or a/an.

So:

• банк can mean the bank or a bank
• заявление can mean the statement/application or a statement/application

Which one is intended depends on context.

In this sentence, English would probably use the bank and the statement/application, but Russian leaves that unstated unless context makes it specific.

Yes, Russian word order is flexible because case endings show grammatical roles.

The neutral order here is:

• Банк принял заявление о несогласии.

But other orders are possible for emphasis, for example:

• Заявление о несогласии банк принял.
  Emphasizes the statement of disagreement
• Принял банк заявление о несогласии.
  Possible, but marked and less neutral

Even with changed word order, the cases still show that:

• банк is the subject
• заявление is the direct object
• о несогласии modifies заявление

It describes заявление.

The structure is:

• Банк = subject
• принял = verb
• заявление о несогласии = object noun phrase

So о несогласии tells us what kind of statement it was.

It does not mean the bank accepted something while disagreeing, and it does not directly describe the bank. It belongs to the noun заявление.

Their dictionary forms are:

• принял → принять
• несогласии → несогласие

To recognize them:

1. принял is a past tense masculine singular verb form. Russian dictionaries list verbs in the infinitive, so you look for принять.
2. несогласии is a case form. Dictionaries list nouns in the nominative singular, so you look for несогласие.

This is a very important reading skill in Russian: identifying the base form from the ending.

Yes, it sounds fairly formal or official.

Words like:

• банк
• принял
• заявление
• о несогласии

fit well in administrative, legal, or business language.

In everyday conversation, people might describe the same situation less formally depending on context. But as written, this sounds like something from a document, letter, or official notice.