We have the functions f and g:
f(x) = 1/x - 2
g(x) = 4/x
To obtain the composite function (f o g)(x):
(f o g)(x) = f(g(x)) = 1/g(x) - 2
Then:
(f o g)(x) = 1/(4/x) - 2
(f o g)(x) = x/4 - 2
Now, to calculate the composite function (g o f)(x):
(g o f)(x) = g(f(x)) = 4/f(x)
(g o f)(x) = 4/(1/x - 2) = 4/((1 - 2x)/x)
(g o f)(x) = 4x/(1 - 2x)