Answer:
[tex]f^{-1}[/tex](x) = [tex]\frac{x-3}{6}[/tex]
Step-by-step explanation:
let y = f(x) and rearrange making x the subject, that is
y = 6x + 3 ( subtract 3 from both sides )
y - 3 = 6x ( divide both sides by 6 )
[tex]\frac{y-3}{6}[/tex] = x
change y back into terms of x, thus
[tex]f^{-1}[/tex](x) = [tex]\frac{x-3}{6}[/tex]