Question

(a) Let A=\ 25,49,81\ ,B=\ 9,16,25,36\ . Find AUB and A-B.​

Answer 1

Answer:

Step-by-step explanation:

A={25,49,81}

B={9,16,25,36}

Then,

AUB = {9,16,25,36,49,81}

notice that 25 is in both A and B. We should not repeat this value in the Union  of two sets.

A-B means the difference of set B from set A OR simply all the elements of set A that are not in set B.

Thus,

A-B={49,81} while B-A = {9,16,36}

Another example is this,

If A = { a, b, c, d, e } and B = { a, e, f, g}, then

A-B = {b, c, d}  and B-A = {f, g}

Hope this helps. :)