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CUET · MATHS · PYQ PAPER 2023

If \(f: R \rightarrow A\) given by \(f(x)=x^2-6 x+12\) is a surjective function, then the set \(A\) is :

  1. A \((3, \infty)\)
  2. B \((-\infty, 3)\)
  3. C \([3, \infty)\)
  4. D \((-\infty, 3]\)
Verified Solution

Answer & Solution

Correct Answer

(C) \([3, \infty)\)

Step-by-step Solution

Detailed explanation

\(x = -\frac{b}{2a} = -\frac{-6}{2(1)} = 3\) \(f(3) = (3)^2 - 6(3) + 12 = 9 - 18 + 12 = 3\) \(\text{Range}(f) = [3, \infty)\) \(A = [3, \infty)\)