If A = {x : x ∈ Z, (x − 1)(x − 2)(x − 3) = 0} and B = {3, 2, 1, 2}, which conclusion is correct?
Answer and explanation
Correct answer: A = B
A product is zero when at least one factor is zero. Hence x − 1 = 0, x − 2 = 0, or x − 3 = 0, giving A = {1, 2, 3}. In set notation, repetition does not create a new element, so B = {3, 2, 1, 2} is also {1, 2, 3}. Order and repeated writing do not affect set equality; therefore A = B.
Frequently asked questions
What is the correct answer to this question?
A = B
Why is this the correct answer?
A product is zero when at least one factor is zero. Hence x − 1 = 0, x − 2 = 0, or x − 3 = 0, giving A = {1, 2, 3}. In set notation, repetition does not create a new element, so B = {3, 2, 1, 2} is also {1, 2, 3}. Order and repeated writing do not affect set equality; therefore A = B.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: The Empty Set, Finite and Infinite Sets, Equal Sets.