Answer:
[tex]g(f(x)) = (2x + 1) - 3 \\ = 2x + 1 - 3 \\ = 2x - 2 \\ \\ f(g(f(x))) = 2(2x - 2) + 1 \\ = 4x - 4 + 1 \\ = 4x - 3[/tex]
I hope I helped you^_^