Answer:
g(x + 8) = 10x + 105 wherever you see it among your answers.
Explanation:
I think I have enough here that I can answer the question, but you should always put in your givens.
f(x) = 10x + 25 Put g(x) where you see x in f(x)
f(g(x)) = 10(g(x) + 25 Put the value for g(x) where you see g(x)
f(x+8) = 10(x + 8) + 25 This might be the answer
From here it is a guess.
f(x+8) = 10x + 80 + 25 Combine the like terms
f(x+8) = 10x + 105