The domain of a function is all values of x the function can assume.
Since this function has a fraction, and any fraction can't have a denominator equal to 0, we have the following condition:
![\begin{gathered} x^2-2x-15\\e0 \\ x\\e\frac{2\pm\sqrt[]{4+60}}{2} \\ x\\e(2\pm8)/(2) \\ x\\e5,x\\e-3 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/high-school/r53pibl8f7et4zyc2d1srwtws8hzsit2im.png)
The variable x can be any real number, except -3 and 5, therefore the domain set is:
![(-\text{inf,}-3)\cup(-3,5)\cup(5,\text{inf)}](https://img.qammunity.org/2023/formulas/mathematics/high-school/cz80ro907ktjttdclp6buyjkd5jlr4usjy.png)