You can put this solution on YOUR website! If it's f(x)= (1/2)x - 1,
-----
Pick 2 values for x and find the corresponding f(x).
Plot the 2 points.
Draw a line thru them.
=============
If it's 1/(2x) - 1 or 1/(2x-1) you'll need more points.
==========
Parentheses are free. Use some.