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Let a be a real number such that the function f(x)=ax^2+6x-15,x∈ R is increasing in (-∞ , 3 4) and decreasing in ( 3 4,∞ ). Then the function…

JEE Main 2021 — Mathematics Calculus

2021mcqeasy

Let aaa be a real number such that the function f(x)=ax2+6x−15,x∈Rf(x)=a{x}^{2}+6x-15,x\in Rf(x)=ax2+6x−15,x∈R is increasing in (−∞,34)(-\infty ,\frac{3}{4})(−∞,43​) and decreasing in (34,∞)(\frac{3}{4},\infty )(43​,∞). Then the function g(x)=ax2−6x+15,x∈Rg(x)=a{x}^{2}-6x+15,x\in Rg(x)=ax2−6x+15,x∈R has a

Official previous-year question

Held on 20 Jul 2021 · Verified 6 Jul 2026.

Options

  1. A

    local maximum at x=−34x=-\frac{3}{4}x=−43​

  2. B

    local minimum at x=−34x=-\frac{3}{4}x=−43​

  3. C

    local maximum at x=34x=\frac{3}{4}x=43​

  4. D

    local minimum at x=34x=\frac{3}{4}x=43​

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