[tex] \frac{ {x}^{2} + 3}{ {x}^{2} - 11x - 12} [/tex]
Because which numbers will make the expessions undefined. We will focus on the denominator only.
Factor the terms.
[tex](x - 12)(x + 1)[/tex]
Now which 2 numbers that will make these terms become 0?
12 and - 1 of course.
So these 2 numbers that will make the expressions undefined are 12 and - 1