I am studying English and I have some confusing in my Algebra Vocabulary, such as:

the "defined condition" of √A is A >=0, (the word "defined condition" is the translation of my language (Vietnamese) "điều kiện xác định" but I don't know exactly the word "defined condition" in Math vocabulary, can anyone show me?

And √A, how do you read it in English (can you write down for me? Is that square root A or...)

Also example:: (x+3)*(2/3x+5) and |x - 2008| how do you read these expression in English?

I am an ESL learner so if I write something wrong, I hope you appreciate and understand my words!!!!
Thanks!

I use this expression a lot when my girlfriend is trying to teach me 5th semester calculus.