Let be the statement 'the quadratic has real roots' and be the statement ''. Which of the following is correct? (Here and are real numbers.)
Answer and explanation
Correct answer: B. is both a necessary and a sufficient condition for
- Step 1: Real roots need .
- Step 2: Rearranging gives , so the two statements are equivalent.
Answer
is both a necessary and a sufficient condition for .
Why not the others: The condition on is just the discriminant condition rearranged; the statements are true for exactly the same pairs .
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