Which of the following is an EMPTY set?
A{x : x is an even prime number}
B{x : x is a real number, x² - 2 = 0}
C{x : x is a rational number, x² - 2 = 0}
D{x : x is a positive integer, x² = 4}
Answer & Solution
Correct answer: C. {x : x is a rational number, x² - 2 = 0}
√2 is irrational — no RATIONAL number satisfies x² = 2, so option C is empty. Option A = {2}, B = {√2, -√2}, D = {2} are non-empty.
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