What is the inverse of f(x)=(x−5)2 for x≥5 where function g is the inverse of function f?

Question

g(x)=x√+5 , x≥0

g(x)=x−5sqrt , x≥5

g(x)=x+5sqrt , x≥−5 <my choice

g(x)=x√−5 , x≥0

Answer 1

x = (g-5)^2
g-5 = ±√x
g = 5±√x

picking one branch, g = 5+√x

Hard to say what all your weird syntax means.

Answer 2

G(x)=(sqrt x)+5, x>=0