Let S be the set of positive integral values of a for which fracax^2 + 2(a + 1)x + 9a + 4x^2 - 8x + 32 < 0, forall x in mathbbR. Then, the number of elements in S is:

Solution & Explanation

### Core Logic For the denominator x^2 - 8x + 32, D = 64 - 128 < 0 and a = 1 > 0. Thus, x^2 - 8x + 32 > 0 forall x in mathbbR. ### Step 1: Constraint on Numerator Since the denominator is always positive, the numerator must be strictly negative for all x in mathbbR. ax^2 + 2(a + 1)x + 9a + 4 < 0 quad forall x in mathbbR This requires a < 0 and D < 0. ### Step 2: Conclusion Since a must be strictly less than 0, there are no *positive* integral values of a that satisfy the condition. Hence, S is an empty set. Number of elements is 0. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Maths: Quadratic Equations

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