Question

How do you find the inverse of `y=2x-4` and is it a function?

Answer 1

inverse: `y=(x+4)/2`
which is a function.

Explanation:

If `y=2x-4`
then
`color(white)("XXX")y+4=2x`
and
`color(white)("XXX")x=(y+4)/2`

Remember that `x` and `y` are arbitrary place holders and we could substitute any other variables in their place.
e.g. `x=(y+4)/2 hArr s=(t+4)/2`

however,it is common to express equations of this type with `y` as the "dependent" variable (that is `y=` some expression based on the "independent" variable "x").

In this case we would write:
`color(white)("XXX")y=(x+4)/2`

Note that since this generates a single value for `y` for any specific value of "x", this expression is a function.