we have the functions
step 1
Find f(g(x))
simplify
therefore
Part 1
If x≥0 the value of f(g(x)) is x
step 2
Find g(f(x))
simplify
therefore
Part 2
If x≥0 the value of g(f(x)) is the same as the first
step 3
Find the inverse of function f(x)
exchange the variables
isolate the variable y
Part 3
the functions f(x) and g(x) are inverse functions