Question

if B={x:x^2=9,2x=4},then B=?​

Answer 1

Yes, X is the empty set.

The set you give is the set of numbers that are both (3 or -3) AND 2. Obviously, no number can be both of these, so X is the empty set.

When you 'AND' two propositions, the result is true if and only if both propositions are true.

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