Can we use via in formal essays (IELTS)? It worries me if the word [STRIKE]are[/STRIKE] is not formal because I have been using it a lot.
I would use "by" unless you know that "via" is part of a fixed expression that you are using.
Look at my red marks in your post above. If you are taking a written exam, you need to make sure you are following the rules of written English:
- Start every sentence with a capital letter.
- End every sentence with a single punctuation mark.
- Always capitalise the word "I" (first person singular).
Check your tense/person agreements. You had written "It worry me" and it should be "It worries me", and "the word are" which should be "the word is" (or "the words are").