Which is the correct roster form of B = {x : x is a prime divisor of 84}?
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Answer and explanation
Correct answer: B = {2, 3, 7} — B = {2, 3, 7}
Prime factorization of 84 is 84 = 2² × 3 × 7. The prime divisors are the distinct prime numbers that divide 84, namely 2, 3, and 7. The factor 4 is not prime, 1 is not prime, and 6 and 14 are composite. A roster form lists each qualifying element once, so B = {2, 3, 7}. Thus option A is correct.
Frequently asked questions
What is the correct answer to this question?
B = {2, 3, 7} — B = {2, 3, 7}
Why is this the correct answer?
Prime factorization of 84 is 84 = 2² × 3 × 7. The prime divisors are the distinct prime numbers that divide 84, namely 2, 3, and 7. The factor 4 is not prime, 1 is not prime, and 6 and 14 are composite. A roster form lists each qualifying element once, so B = {2, 3, 7}. Thus option A is correct.
Which subject and chapter does this question cover?
This is a Class 12 Mathematics question. Chapter: Sets.
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