Answer:
[tex]$ \frac{(y + 1)}{3} $[/tex]
Step-by-step explanation:
Call [tex]$ f(x) = y = 3x - 1 $[/tex]
Now, [tex]$ y + 1 = 3x $[/tex]
[tex]$ \implies \frac{y + 1}{3} = x $[/tex]
This is the inverse of the given function.
You can cross - verify it by substituting a point, say, [tex]$ (1,3) $[/tex]
We see that the point satisfies both the equations.
