F(x)=5x-9 g(x+1)=3x+1 f{g(x)}=???

F(x) = 5x – 9

g(x + 1) = 3x + 1
g(x + 1) = 3(x + 1) – 2
g(x) = 3x – 2

f(g(x))
= 5(3x – 2) – 9
= 15x – 10 – 9
= 15x – 19