Let x be the greater real root of x^2 + x − 20 = 0 and y be the greater real root of y^2 − y − 30 = 0. Compare x and y and choose the correct relation.

Difficulty: Easy

Correct Answer: If x < y

Explanation:


Introduction / Context:
The original statement was ambiguous because each quadratic has two roots. Applying the Recovery-First Policy, we define x and y explicitly as the greater real roots. We then compare these values by solving each quadratic via factoring.


Given Data / Assumptions:

  • x solves x^2 + x − 20 = 0 and is the greater root.
  • y solves y^2 − y − 30 = 0 and is the greater root.
  • We compare x to y.


Concept / Approach:
Factor each quadratic to get roots quickly. For ax^2 + bx + c with small integers, try integer factor pairs of c that sum to b. Identify the larger root in each case and compare.


Step-by-Step Solution:

x^2 + x − 20 = 0 ⇒ (x + 5)(x − 4) = 0 ⇒ roots: −5, 4 ⇒ greater x = 4.y^2 − y − 30 = 0 ⇒ (y − 6)(y + 5) = 0 ⇒ roots: 6, −5 ⇒ greater y = 6.Therefore x = 4 and y = 6 ⇒ x < y.


Verification / Alternative check:
Quadratic formula gives identical results; factoring is sufficient here.


Why Other Options Are Wrong:
x > y or x ≥ y contradict the computed values; equality does not hold.


Common Pitfalls:
Not clarifying which root is used; comparing mismatched (e.g., larger with smaller) roots gives inconsistent relations.


Final Answer:
If x < y

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