Which is the correct roster form of M={x∈Z: x²=1}?
Answer and explanation
Correct answer: M={-1,1}
Solve the defining equation over the integers: x²=1. Taking square roots gives x=1 or x=−1, and both values are integers. Verification confirms that 1²=1 and (−1)²=1. Therefore the roster form is M={−1,1}, so option B is correct. Option A omits the negative solution, option C includes 0 even though 0²=0, and option D incorrectly treats the solution set as empty.
Frequently asked questions
What is the correct answer to this question?
M={-1,1}
Why is this the correct answer?
Solve the defining equation over the integers: x²=1. Taking square roots gives x=1 or x=−1, and both values are integers. Verification confirms that 1²=1 and (−1)²=1. Therefore the roster form is M={−1,1}, so option B is correct. Option A omits the negative solution, option C includes 0 even though 0²=0, and option D incorrectly treats the solution set as empty.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Number Systems. Topic: General chapter practice.
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