Answer: -127
Explanation:
They are giving you the corresponding x value for which you should plug into the function. So plug 4 into g(x) and plug 4 into f(x). Then subtract them
g(x) = -3(4) + 4 = -8
Im assuming that is

f(x) = 8(4)^2 - 9 = 119
Now do -8 - 119 to get -127