Start from [tex] f(x) = 2x - 9 [/tex]
When you vertically translate the graph of a function, you are adding a constant to that equation, i.e. you're performing the transformation
[tex] f(x) \to f(x) + k [/tex]
You translate the function [tex] k [/tex] units up if [tex] k>0 [/tex] and k units down if [tex] k<0 [/tex]
So, in your case, you have to add 6 to the function:
[tex] f(x) = 2x - 9 \to g(x) = f(x) + 6 = 2x - 9 + 6 = 2x - 3 [/tex]
