Answer
f is not one-to-one,
and has no inverse.
Work Step by Step
This function is not one-to-one,
Its graph IS a horizontal line so it fails the Horizontal Line Test.
Another way to show this is to select any two values for x,
e.g. x=0 and x=1,
and, since
$f(0)=f(1)=-3$
(more than one x has the same function value),
so f is not one-to-one on its domain.
It, then, has no inverse.
