C
let y = f(x)
Then rearrange making x the subject
y = - [tex]\frac{2}{3}[/tex] x - 18 ( add 18 to both sides )
y + 18 = - [tex]\frac{2}{3}[/tex] x
multiply both sides by - [tex]\frac{3}{2}[/tex]
- [tex]\frac{3}{2}[/tex] (y + 18) = x
x = - [tex]\frac{3}{2}[/tex] y - 27
change y to x for inverse function
[tex]f^{-1}[/tex](x) = - [tex]\frac{3}{2}[/tex] x - 27 → C