JEE Main 2024MathematicsQuadratic EquationEasyMCQ

JEE Main 2024Quadratic Equation Question with Solution

JEE Main 2024 (31 Jan Shift 1)

Question

Let S be the set of positive integral values of a for which ax2+2a+1x+9a+4x2-8x+32<0, x. Then, the number of elements in S is:

Choose an option

Show full solutionCorrect option: B
Correct answer
B0

Step-by-step explanation

Given:

 ax2+2(a+1)x+9a+4x2-8x+32<0  xR

For quadratic x2-8x+32=0,  D1=-82-432=-64

Since the discriminant is less than zero and the leading coefficient is positive, this quadratic will always be positive.

Now, solving ax2+2(a+1)x+9a+4<0

We know that, for a quadratic to be always negative, the coefficient of x2<0, D<0.

a<0 

But we want positive values.

So, no positive integral value exist.

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About this question

This is a previous-year question from JEE Main 2024, 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.