Khảo sát danh thu hàng tháng của một công ty quảng cáo người ta thu được kết quả 130, 140,210,184,225,150,190. Tính độ lệch mẫu đã hiệu chỉnh S

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

In the xy-plane, if the parabola with equation passes through the point (-1, -1), which of the following must be true?

1- what do you think the product of a nonzero rational number and an irrational number is? is it rational or irrational? make use of variables, the closure property of integers, and possibly a proof by contradiction to prove your hypothesis.2- why do we have to specify that the rational number must be nonzero when we determine what the product of a nonzero rational number and an irrational number is? if the rational number were 0, would it give us the same result we found in the first question?