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| Question 1091471:  Let N = set of natural numbers;
 Z = set of integers;
 Q = set of rational numbers;
 Q' = set of irrational numbers; and
 R = set of real numbers
 Find the following sets:
 (Z ∩ Q) U N =
 (Q U Q') ∩ R =
 (N U Z) U (Q ∩ R) =
 (Q U R) ∩ N =
 (Q U N)' ∩ R =
 Q' ∩ Z =
 
 *the options for the answers are: null set {}, Q, Z, N, R, and Q', but I can't get why. For example, for the first item, I tried finding what Z and Q had in common before having it in union with N, but I'm used to having this done with actual sets with elements... hence, I honestly don't know how to answer this.
 Answer by ikleyn(52879)
      (Show Source): 
You can put this solution on YOUR website! . Let N = set of natural numbers;
 Z = set of integers;
 Q = set of rational numbers;
 Q' = set of irrational numbers; and
 R = set of real numbers
 Find the following sets:
 
 
 
(Z ∩ Q) U N =            a)   (Z ∩ Q) = Z (it is obvious and even more than obvious);
                         b)  Therefore,  (Z ∩ Q) U N = Z U N = Z  (again, it is obvious and even more than obvious).
(Q U Q') ∩ R =           a)  (Q U Q') = R (it is obvious);
                         b)  Therefore,  (Q U Q') ∩ R = R ∩ R = R  (it is obvious).
(N U Z) U (Q ∩ R) =      a)  (N U Z) = Z;  (Q ∩ R) = Q  (obvious)
                         b)  Therefore,  (N U Z) U (Q ∩ R) = Z U Q = Q.
(Q U R) ∩ N =
(Q U N)' ∩ R =
Q' ∩ Z =
*the options for the answers are: null set {}, Q, Z, N, R, and Q'
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 And so on . . .    From this point,  go ahead on your own.
 
 I don't want to do ALL this simple work instead of you.
 
 It is REALLY very SIMPLE.
 
 
 
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