Question

if A={ X:X is a prime number X<20} B={X:X=2m+3,0<m<9,mEz}
then find A-B,B-A and ( A-B) U ( B-A)​

Answer 1

Answer:

A can hold any values out of 2,3,5,7,11,13,17,19

m can take any values from 1 to 8 , so corresponding values for B are 5, 7, 9, 11, 13, 15, 17.

Now A - B = [2, 3, 19]

B - A = [ 9, 15]

So ( A-B) U ( B-A) = [ 2, 3, 9, 15, 19]