Q. If $f:R \rightarrow R$ and $g:R \rightarrow R$ are defined by $f(x) = x - 3$ and $g(x) = x^{2} + 1$, then the values of $x$ for which $g\left\{ f(x) \right\} = 10$ are

A) $0,\ - 6$
B) $2,\ - 2$
C) $1,\ - 1$
D) $0,\ 6$
Explanation

(d)
Given, $f(x) = x - 3,\ \ g(x) = x^{2} + 1$
$\therefore\ \ \ \ \ \ \ g\left\{ f(x) \right\} = g(x - 3)$
$\Rightarrow \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ 10 = (x - 3)^{2} + 1$
$\Rightarrow \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ 10 = x^{2} + 10 - 6x$
$\Rightarrow \ \ \ \ \ \ \ \ \ \ \ x(x - 6) = 0 \Rightarrow x = 0,\ 6$

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.