25 PoInTs!! PlEaSe HeLp!! WiLl GiVe BrAiNlIeSt!!!
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.

[tex]f(x) = \frac{x + a}{b}[/tex]
[tex]g(x) = cx - d[/tex]

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!!!