Inverse Functions: Given y = f(x) , Find x = g(y)

i.e. given a function expressed in terms of  y  as a function of x
find the inverse which is x as a function of y:

Example:  y = x + 4, inverse is x = y - 4
 

Function Manipulations:

Given f(x), g(x) - Find h(x) = f(g(x)) - substitution at various levels of a many
related functions.