Question

If $f:R\to R$ be mapping defined by $f(x)=x^3+5$ then $f^{-1}(x)$ is equal to

• A. ${\left(x+5\right)}^{1/3}$
• B. ${\left(x-5\right)}^{1/3}$
• C. ${\left(5-x\right)}^{1/3}$
• D. $5-x$

Answer 1

Answer: (B)

Let $y=f(x)=x^3+5$
$\Rightarrow x=(y-5{)}^{1/3}$
$\therefore f^{-1}(x)=(x-5{)}^{1/3}$