Are the following statements true :

1. A Ç B¢ = ÆÞ A Ì B

But I think it should be

A Ç B¢ = ÆÞ A Í B

2. A¢È B = U Þ A Ì B

But I think it should be

A¢È B = U Þ A Í B

3.(A – B) È B = A iff B Ì A

But I think it should be

(A – B) È B = A iff B Í A

Plz tell me I am wrong or book is wrong. Plz give ur answer with reason. I don’t want mathematical proof for the correct statements. If possible , plz verify the statement that u say correct or wrong.