Which of the following statements are true : Let A and B are two sets. If `x in A` and `B sube A`, then `x in B`.

If A sube B and B sube A then A=B

If A and B are two sets then A sube B hArr B'sube A'

If B' sube A' then A sube B

Which of the following statement is not correct? Given X is universal set, A and B are two sets:

Let A and B are two sets such that A sube B , then A ∪ B = ........

Which of the following statements are true? Give reason to support your answer.For any two sets A and B either A sube B or B sube A

Whether the following statement is true ? Justify your answer. For any two sets A and B either A sube B or B sube A.

For any two sets A and B prove that If A sube B then B' sube A'