$4.)($i$)$ Glven

$f(x)=5-4x$

If possible, find its inverse function $f^{-1}(x)$ and check your answer.

$($ii$)$ SOLVE for $x$ :

$2^{x-5}=3$

$($iii$)$ Evaluate:

${\displaystyle \underset{1}{\overset{e}{}}}\frac{x^2+x+1}{x}dx$