Difficulty: Easy
Correct Answer: both of them are integers
Explanation:
Introduction / Context:We analyze the quadratic x^2 − x − 2 = 0 to determine qualitative properties of its roots. Factoring cleanly reveals exact integer solutions, allowing us to evaluate each statement provided.Given Data / Assumptions:
Concept / Approach:Factor to find roots. Then check whether both are integers, both natural numbers, or whether a specific sign statement holds.Step-by-Step Solution:
x^2 − x − 2 = (x − 2)(x + 1) = 0.Roots are x = 2 and x = −1.Both are integers; only one of them (2) is a natural number if we adopt the common convention that natural numbers are positive integers starting from 1.Verification / Alternative check:Plug back: 2^2 − 2 − 2 = 0 and (−1)^2 − (−1) − 2 = 1 + 1 − 2 = 0.
Why Other Options Are Wrong:
Common Pitfalls:Depending on definitions of “natural numbers.” Most exams use 1,2,3,…, thus excluding −1 and 0.
Final Answer:
both of them are integers
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