Using the two functions listed below, insert numbers in place of the letters a, b, c, and d so that f(x) and g(x) are inverses.


My teacher told me to just make up any number for the variables a, b, c, d and plug them in. So I made up these numbers:

A: 3
B: 5
C: 7
D: 9
***These are supposed to be substituted into the the equations above!!***

However, when I plug them into the equation of f(x), it doesn't equal the equation of g(x). Did I do something wrong? Please help!!!