Question

What is the inverse function of `y= -3`?

Answer 1

The function `f(x) =-3` does not have an inverse function.

Explanation:

A function `f` has an inverse if we can determine, without saying "or" from the `y` value, what the `x` value was.

We would need to be able answe with ceratinty, "Waht one number MUST have been the input (the `x` value) have been, if the output (the `y` value was this?.

Clearly, in this example, knowing the `y` value (`3`) does NOT tell me the ONE `x` value we must have used. `x` could have been anything.

Compare this to the function `f(x) = 2x+1`. If you tell me the output, I can work backwards to the input without saying "OR". (Functions do not say "OR". The give one answer, never two or more.)