Identify the vertical asymptotes of f(x) = quantity x plus 6 over quantity x squared minus 9x plus 18.

Rewriting the function



The vertical asymptotes will be at the value of  when the denominator is zero

 ⇒ factorising 

and 

The value of  must not be at 3 and 6 because we cannot have the domain of the denominator equal to zero (fraction with zero denominators is undefined)

Hence, vertical asymptote is at  and