Question

f f (x) = 5 x minus 25 and g (x) = one-fifth x + 5, which expression could be used to verify g(x) is the inverse of f(x)?

Answer 1

B. One-fifth (5 x minus 25) + 5

Explanation:

Just got it right on the test.

Answer 2

We study if the composition of both functions equals the identity ("x"), that is if

`f(g(x))=x`

Explanation:

The composition of the two functions should render 'x" if one is the inverse of the other. That is, we need to find what
`f(g(x))` renders. Notice as well that the same verification could be done with examining
`g(f(x))`.

Let's work with
`f(g(x))` :

`f(g(x))=f((1)/(5) x+5)=5\,((1)/(5) x+5)-25= x+25-25=x`

So we see that the composition of both functions indeed render "x", and that way we have verified that one is the the inverse of the other.