Answer
See graph.
domain $(-\infty,\infty)$, range $(-\infty,9)$, H.A. $y=9$.
Work Step by Step
Step 1. To obtain the graph of $f(x)=9-3e^{-x}$ from $y=e^x$, reflect the curve across the y-axis, stretch vertically by a factor of 3, reflect across the x-axis, then shift 9 units up. See graph.
Step 2. We can determine the domain $(-\infty,\infty)$, range $(-\infty,9)$, horizontal asymptote H.A. $y=9$.
