Rationalize the denominator and simplify

Determine whether the set of whole numbers is closed under addition. explain why the set is or is not closed. give an example.

The data represents the semester exam scores of 8 students in a math course. {51,91,46,30,36,50,73,80} what is the five-number summary?

7. if the value of x varies directly with the value of y, and x = 3 when y = 21. what is the valu y, and x = 3 when y = 21. what is the value of x when y = 105?