Answer
vertical asymptote $x=-3$,
end behavior $y=2x$.
Work Step by Step
1. Use synthetic division for $f(x)$ as shown in the figure, we get $f(x)=2x+\frac{6}{x+3}$.
So this function has a slant asymptote $y=2x$
2. Graph both functions as shown in the figure. We can identify the vertical asymptote as $x=-3$,
3. An overview of both curves shows that they have the same end behavior of $y=2x$.
