JEE Main 2021MathematicsQuadratic EquationEasyMCQ

JEE Main 2021 — Quadratic Equation Question with Solution

JEE Main 2021 (25 Feb Shift 1)

Question

The integer k, for which the inequality x2-23k-1x+8k2-7>0 is valid for every x in R is:

Choose an option

Show full solutionCorrect option: C
Correct answer
C3

Step-by-step explanation

x2-23k-1x+8k2-7>0

Now, D<0

⇒ 43k-12-4×1×8k2-7<0

⇒ 9k2-6k+1-8k2+7<0

⇒ k2-6k+8<0

⇒ k-4k-2<0

⇒ k∈2,4

⇒k=3

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About this question

This is a previous-year question from JEE Main 2021, covering the Quadratic Equation chapter of Mathematics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.