If the expression is [tex]\frac{8}{ \text{x} } + 9[/tex], then x = 0 must be excluded from the domain to avoid a division by zero error.
Or
If the expression is [tex]\frac{8}{ \text{x} + 9}[/tex], then x = -9 must be excluded from the domain to avoid a division by zero error. This time the +9 is in the denominator. Note how x+9 = 0 leads to x = -9.
