Answer
domain $(-\infty,\infty)$, range $(-\infty, 1]$, function.
Work Step by Step
Step 1. Rewriting the equation as $x^2-4x+4=-y-3+4$ or $(x-2)^2=-(y-1)$, we see that the parabola opens downwards with a vertex at $(2,1)$.
Step 2. We can find the domain as $(-\infty,\infty)$ and range as $(-\infty, 1]$
Step 3. The relation is a function as it will pass a vertical line test.
