Question

If $f$ : $R\to R$ defined by $f\left(x\right)=\frac{2x-7}{4}$ is an invertible function, then find $f^{-1}$.

• A. $(4x+5)/2$
• B. $(4x+7)/2$
• C. $\frac{3x+2}{2}$
• D. $\frac{9x+2}{5}$

Answer 1

Answer: (B)

let $y=\frac{2x-7}{4}$
$\Rightarrow x=\frac{4y+7}{2}$
$\therefore f^{-1}\left(y\right)=\frac{4y+7}{2}$
$\Rightarrow f^{-1}\left(x\right)=\frac{4x+7}{2}$