Solution:
Consider the following functions:
[tex]f(x)=x^5[/tex]and the composition:
[tex]h(x)=f(g(x))=(x+7)^5[/tex]Note that if
[tex]g(x)=x+7[/tex]we get:
[tex]h(x)=f(g(x))=f(x+7)=(x+7)^5[/tex]So that, we can conclude that the correct answer is:
[tex]g(x)=x+7[/tex]