Hello, thank you for taking the time to post your question!
When it says to find g(6), that means that you want to plug in x = 6 in the original g(x) function
g(6) = 3(6) – 3
=18 – 3
=15
I hope that helps get you moving in the right direction! Feel free to reach out if you have any additional questions beyond that :)
Rylee V.
08/26/14