Question

Which pair(s) of functions are inverses? There may be more than one correct answer.


a.) f(x) = x - 12, g(x) = x + 12
b.) f(x) = 3x, g(x) = 1/3x
c.) f(x) = 4x, g(x) = -4x
d.) f(x) = 2x + 1, g(x) = 2x - 1


Would the answer be just letter B.)?

Answer 1

A and B are inverses.

(you can check by picking any number, subbing that into the original function. Take that answer and sub it into the "inverse" function. If you don't get back the original number it is not a true inverse.
e.g. for D
let x = 3
f(3) = 7
f(7) = 13 , not an inverse

e.g. for A
let x = 4.56
f(4.56) + 4.56 - 12 = -7.44
g(-7.44) = -7.44 + 12 = 4.56 , YUP!!