Answer:
[tex]f^{-1}[/tex](x) = [tex]\frac{x+6}{7}[/tex]
Step-by-step explanation:
Let y = f(x) and rearrange making x the subject, that is
y = 7x - 6 ( add 6 to both sides )
y + 6 = 7x ( divide both sides by 7 )
x = [tex]\frac{y+6}{7}[/tex]
Change y back into terms of x, hence
[tex]f^{-1}[/tex](x) = [tex]\frac{x+6}{7}[/tex]