Can someome me find the mean of this numbers? 15,16,17,18,19,20,21,22 (random anxwers will be reported)

Write an algebraic expression to match each statement a. four less than 8 times a number b. twice the difference of a number and six c. nine from a number squared

If cos(2x) = tan^2(y), show that cos(2y) = tan^2(x).

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?