Answer
$1$
Work Step by Step
Without actually multiplying, we can see that the polynomial in the numerator has degree 2, and the leading coefficient is $a_{2}=1$.
The polynomial in the denominator has degree 2, and the leading coefficient is $b_{2}=1$.
By the procedure "Finding asymptotes..." on page 336,
$y=\displaystyle \frac{a_{n}}{b_{n}}=\frac{1}{1}=1$
$y=1$ is the horizontal asymptote
Fill the blank with: $1$
