# How do you find all the values that make the expression undefined: (3x^2 - 3)/(6x - 6)?

Thus, this expression becomes undefined when $6 x - 6 = 0$, thus, when $x = 1$.
In this case, by the way, we'd have an interesting topic in calculus: $\frac{0}{0}$, but that's not the case for now.
So, your answer: this function becomes undefined only when $x = 1$.
Besides, when $x = \pm 1$, your numerator becomes zero, but when $x = - 1$, then your numerator would be $- 12$, and thus, you function, $\frac{0}{- 12} = 0$, and zero is a defined value.