Nature of roots for x^2 − x − 2 = 0: Which statement is correct about its two roots?

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:

  • Equation: x^2 − x − 2 = 0.


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:

  • both of them are natural numbers: False since −1 is not natural.
  • the latter of the two is negative: Ambiguous phrasing; the set has one negative and one positive. A clearer property is “one root is negative and one is positive.”
  • None of these: Incorrect because “both integers” is true.


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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