I really need help understanding ho to solve combination functions

Question

here is a specific problem I am struggling with.

Let f(x) = x - 2 and g(x) = x^2 - 7x - 9. Find f(g(-1)).

Answer 1

g(x) = x^2 - 7x - 9
g(-1) = (-1)^2 - 7*(-1) - 9 = -1

F(g(-1)) = F(-1)

F(x) = x - 2
F(-1) = -1 - 2 = -3.