What is the answer to this, and how did you arrive there, please help!?

Question

Determine whether the pair of functions f and g are inverses of each other.

f(x) = x + 7 and g(x) = x - 7

Answer 1

The inverse of a function is where you reverse the x and y variables.

f(x):
y = x + 7

Inverse function:
x = y + 7

Solve for y:
y = x - 7

This is equivalent to g(x) so they are inverses.

Answer 2

find f o g and g o f and if they both = x, the functions are inverses.

f o g = (x - 7)+ 7 replacing the x in f(x) with the x - 7 of g
f o g = x

g o f = (x + 7) - 7 = x also

Answer 3

they are!