Answer :
Formula for inverse function:
[tex]d^{-1}(y)=?\\y=2x-4\\2x=y+4\\x= \frac{y+4}{2}\\ d^{-1}(y)= \frac{y+4}{2} [/tex]
[tex]d^{-1}(y)=?\\y=2x-4\\2x=y+4\\x= \frac{y+4}{2}\\ d^{-1}(y)= \frac{y+4}{2} [/tex]
[tex]y=2x-4 \\
Replace \ x \ by \ y:\\
x=2y-4\\
Isolate \ y:\\
2y=x+4\\
y=\frac{x+4}{2}\\
\\
\boxed{d^{-1}(x)=\frac{x+4}{2}}[/tex]