Question

Need help understanding this problem please

Answer 1

f(g(x)) is a composite function:

$f(g(x))=f(\sqrt{x+5})=2\sqrt{x+5}-1$

Plug in x = 4:

$f(g(4)) = 2\sqrt{4+5}-1=2\sqrt9-1=2\cdot3-1=\boxed{5}$

so the answer is C.