Question:
If the functions $f : R \rightarrow R , g : R \rightarrow R$ are defined as $f(x) = 2x +3, g(x) = x^2 + 7$ and $f[g(x)] = 25$ then $x = $
If the functions $f : R \rightarrow R , g : R \rightarrow R$ are defined as $f(x) = 2x +3, g(x) = x^2 + 7$ and $f[g(x)] = 25$ then $x = $
Updated On: Jul 6, 2022
- $f(x) $
- $\pm 2$
- $\pm 3$
- $\pm 4$
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The Correct Option is B
Solution and Explanation
$f(g(x)) = 25\: \Rightarrow \: 2g(x) + 3 = 25$
$\Rightarrow \, g(x) = 11 \Rightarrow x^2 + 7 = 11 \Rightarrow x = \pm 2$
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