Question

I really really need this question answered:

Consider the following function.

y= 1/(x-8)^3


Which two functions below make up a composite function form for y?

y=1/u
u=1/x
u=x-8
y=u^3
y=u^-3
u=x^3

Answer 1

if we assume u=(x-8)^3
then y=1/u

Answer 2

yes but i can only choose 2 of the functions..

Answer 3

if u=(x-8), then y=u^-3

Answer 4

y=u^-3 , y=1/u