Given the functions:
f(x)=1/4x+5
g(x)=4x-20
The functions g and f are said to commute with each other if g ∘ f = f ∘ g.
Let's check the functions if they are commutative.
a.) f ∘ g = f(g(x))
b.) g ∘ f = g(f(x))
Conclusion:
g ∘ f = f ∘ g
Therefore, the functions are commutative.