Quantitative Modeling
Moving Averages???

For what values of the variable x is the expression square root of 7x+14+ square root of 7-x a real number?

Which questions would most a reader identify the author's purpose for writing? check all that apply. what type of text is this? what type of reviews did the book receive? how many copies of the book have been sold? what is the central idea? how does this text make one feel?

Which one is the correct answer, and why?