The two functions are 1st degree polynomial, so they are both lines.
In order to draw a line, you have to sample two points and connect them.
To sample points from an equation, choose any value for x and compute the correspondent value for y.
For example, if we choose x=0 and x=1 for the first equation, we have
![f(x)=3x-2 \implies f(0)=-2,\quad f(1)=1](https://tex.z-dn.net/?f=f%28x%29%3D3x-2%20%5Cimplies%20f%280%29%3D-2%2C%5Cquad%20f%281%29%3D1)
So, the line passes through the points
and ![(1,1)](https://tex.z-dn.net/?f=%281%2C1%29)
Similarly, if we choose x=0 and x=3 for the first equation, we have
![f^{-1}(x)=\dfrac{x}{3}+\dfrac{2}{3} \implies f(0)=\dfrac{2}{3},\quad f(3)=1](https://tex.z-dn.net/?f=f%5E%7B-1%7D%28x%29%3D%5Cdfrac%7Bx%7D%7B3%7D%2B%5Cdfrac%7B2%7D%7B3%7D%20%5Cimplies%20f%280%29%3D%5Cdfrac%7B2%7D%7B3%7D%2C%5Cquad%20f%283%29%3D1)
So, this line passes through the points
and ![(3,1)](https://tex.z-dn.net/?f=%283%2C1%29)
If you draw the two points for each line and connect the pairs, you'll have the two lines.