First, change the values of x for y, and y for x in the first function:
[tex]x = 2y + 6[/tex]
Organize the equation in terms of y.
[tex]x = 2y + 6 \\ 2y = 6 - x \\y = \frac{6 - x}{2} \\ y = 3 - \frac{1}{2} x[/tex]
Given that f^-1(x) is 3-1/2x, each of the given functions are not inverses of each other.