Show that if a cb, then a = b ( b a ). show that if a c b, then a u (b \ a) = b. show, by example, that for sets a, b, and c, an b = an c does not imply b = c.

If A ⊂ B, then A = B \ ( B \ A)

ok, when you do B \ A, you are subtracting all the elements in A∩B from B. So the only elements remaining are those who aren't in A.

If we subtract this of B again, we are subtracting of B all the elements that aren't in A, so the only elements remaining are those who belongs in A.

If A ⊂ B then A U (B \ A) = B.

Again, when you do B \ A you are extracting all the elements that belongs to the A∩B from B. So you are extracting al the elements from A. and when you add all the elements of A again, then you recuperate B.

if AnC = AnC does not imply that B = C.

if A = {1,2}, B = {1,2,3,4,5} and C = {1,2,3}

then AnC = {1,2} and AnB = {1,2} but B and C are different.

correct answer:

b.(19,-2)

answer: what is the conflict?

step-by-step explanation:

*what has happened to new york city?

*what is in the time capsule?

* what did the kidz see that gave them hope?

*what will they do with what they find?

* how will they save the city?

* what challenges will they face along the way?

*what big choice will they make at the climax of the story?

* what lesson do they learn at the end of the story?