No. "Of a city" needs to modify a preceding noun, and "northern" is an adjective, rather than being a noun. But "northern part of a city" or "north of a city" would both be okay, because "part" and "north" can be nouns.
I don't understand why "of a city" needs to modify a preceding noun, however (if that is really true). In some other examples, a prepositional phrase with "of" can go with a preceding adjective -- for instance in "desirous of being chosen".
No, it is not correct grammar to say "northern of a city." Instead, you should say "northern part of the city" or "north of the city" to convey the same meaning.
No, the grammar is not correct. The correct way to say it is "You have to have it cleaned."
No, "Is was able to confirmed" is not correct grammar. The correct phrase would be "It was able to be confirmed."
No, it is not proper grammar. The correct phrasing is "you and I."
No, the correct grammar would be "Look at what you got."
Yes, "you were correct" is correct grammar. This sentence is in the past tense and conveys that someone was right about something.
Yes, that is correct grammar.
No, the grammar is not correct. The correct way to say it is "You have to have it cleaned."
This should say, The next stop will be somewhere in Vasayas, then it will be correct grammar. Written as it is it is not on correct grammar.
No, it is not correct
No, "Is was able to confirmed" is not correct grammar. The correct phrase would be "It was able to be confirmed."
No, it is not proper grammar. The correct phrasing is "you and I."
No, the correct grammar would be "Look at what you got."
Yes, "you were correct" is correct grammar. This sentence is in the past tense and conveys that someone was right about something.
Yes
Absolutely.
No, The correct grammar for this sentence would be, "He finished doing his homework."
Yes, it is correct to say out of compliance with. It means out of help with in English grammar.