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WBJEE · Maths · Basic of Mathematics

If \(\log _{e}\left(x^{2}-16\right) \leq \log _{e}(4 x-11)\), then

  1. A \(4 < x \leq 5\)
  2. B \(x < -4\) or \(x>4\)
  3. C \(-1 \leq x \leq 5\)
  4. D \(x < -1\) or \(x>5\)
Verified Solution

Answer & Solution

Correct Answer

(C) \(-1 \leq x \leq 5\)

Step-by-step Solution

Detailed explanation

Given, \(\log _{e}\left(x^{2}-16\right) \leq \log _{e}(4 x-11)\) if and only if \(\begin{array}{l} x^{2}-16 \leq 4 x-11 \\ \Rightarrow x^{2}-4 x-5 \leq 0 \\ x^{2}-5 x+x-5 \leq 0 \\ \Rightarrow x(x-5)+1(x-5) \leq 0 \\ (x-5)(x+1) \leq 0 \end{array}\) Sign scheme of…