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Question: Answered & Verified by Expert
Let \( f: R \rightarrow R \) be defined by \( f(x)=2 x+6 \) which is a bijective mapping then \( f^{-1}(x) \) is given by
MathematicsFunctionsKCETKCET 2016
Options:
  • A \( \frac{x}{2}-3 \)
  • B \( 2 x+6 \)
  • C \( x-3 \)
  • D \( 6 x+2 \)
Solution:
2434 Upvotes Verified Answer
The correct answer is: \( \frac{x}{2}-3 \)
Given that $f(x)=2 x+6, f: R \rightarrow R$
Let $y=2 x+6$ then, $2 x=y-6$
$\Rightarrow x=\frac{y-6}{2}$
Now, $y=\frac{x-6}{2}$
$=\frac{x}{2}-3$
Therefore, $f^{-1}(x)=\frac{x}{2}-3$

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