(f o g)(x) is the composition of function where we substitute one function into other function.
So, (f o g)(x) = f( g(x) )
The given functions are f(x) = -8x+6 and g(x) = x³.
So,we need to plug in x³ for g(x) in f(x). Therefore,
(f o g)(x) = f( g(x) )
= f (x³) Replace g(x) with x³.
= -8x³ + 6 Replace x³ with x in f(x).
So, (f o g)(x) = -8x³ + 6.