For what real values of a is the expression (a + 3)/(a^3 - a) undefined? List your answers in increasing order separated by commas.
+2668 For the expression to be undefined, it has to be \(x \over 0\). The only ways to get \(a^3-a\) equal to \(0 \) is when \(a \) is \(\color{brown} -1, 0, 1 \)
