which expression could be used to verify that g(x) is the inverse of f(x)?

Answer:
Third option:
[tex]\frac{1}{3}(3x)[/tex]
Step-by-step explanation:
f(x)=3x
[tex]g(x)=\frac{1}{3}x[/tex]
To verify that g(x) is the inverse of f(x) we can find:
[tex]f(g(x))=f(\frac{1}{3}x)=3(\frac{1}{3}x)[/tex]
or:
[tex]g(f(x))=g(3x)=\frac{1}{3}(3x)[/tex]
Then the answer is third option:
[tex]\frac{1}{3}(3x)[/tex]