If the function f (x) = mx + b has an inverse function, which statement must be true?

F (x) = mx + b is just equal to the equation

y = mx + b

In order for us to get the inverse function, then we can interchange x to y and y to x

y = mx + b

x = my + b

Then we need to find y

x = my + b

-my = - x + b

my = x - b

y = (x-b) / m

f (x) = (x - b) / m