Answer:
They are inverses since both composition equal x.
Step-by-step explanation:
Given the functions, f(x) = 3x + 1 and g(x) = (x-1) / 3, to check if they are inverses functions, we are to find the inverse of one of the function and check if it will give us the other function.
Let's look for the inverse of f(x).
Given f(x) = 3x+1
Let y = f(x) so that y = 3x+1
Replace y with x
x = 3y+1
Make y the subject of the formula of the resulting equation;
3y = x-1
y = (x-1)/3
The new function of x will be the inverse of f(x)
Hence f^-1(x) = (x-1)/3 = g(x)
Another way to check is to find their composition. Let's find f(g(x) and g(f(x)
F(g(x)) = f((x-1)/3)
Replace x with (x-1)/3 in f(x)
F(g(x)) = 3[(x-1)/3]+1
F(g(x)) = x-1+1
F(g(x)) = x
Similarly for g(f(x));
g(f(x)) = g(3x+1)
Replace x in g(x) with 3x+1
g(3x+1) = (3x+1-1)/3
g(3x+1) = 3x/3
g(3x+1) = x.
Since g(f(x)) = f(g(x)) = x, hence f(x) and g(x) are Inverses functions
