Question

How do you graph `f(x)=3 sqrt (x-8)`?

Answer 1

You can make a table of values for `f(x)` for various values of `x`
Remember that our functions is defined for `x>=8`

Hence its graph is

You can go to the link below where i have setup a desmos page to play with various values of f(x) which are then plotted so you get a feeling of the whole process.

desmos files for plotting f(x)