I am lost on this question. Can you break all of it down for me, please?

A function g is given by g(x) -x 12 +6 g(x +h) -g(x) Find g( - 8), g(0), g(9). g(a + h), and h g( - 8) = (Simplify your answer.) g(0) = (Simplify your answer.) g(9) = (Simplify your answer.) g(a + h) g(x + h) - g(x) h