I presum you mean . Just go ahead and divide it out: divided by is equal to x+ a fraction with lower degree in the numerator than in the denominator. Thus, y= x+ n is a slant asymptote.

The only "technical" points are for n= 2, where the fraction is which is equal to x+ 2 for all x not equal to 2- would you call that an asymptote?- and n= 1 where the fraction is which does not exist.