using long division to find the oblique asymptote of rational function

Question

To find the oblique asymptote of a rational function, the book I'm reading says to divide the denominator of a fraction into the numerator. The example rational function it gives is $$\frac{x^2 - 9} {x + 2}.$$ The result of the long division it says to perform is $x - 2$. However when I divide $\frac{x^2 - 9} {x +2}$ I get $x - 5$. Is the answer in the book $x - 2$ incorrect, or am I performing the long division incorrectly by getting $x - 5$ as the quotient?