Question

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Answer 1

@tcarroll010

Answer 2

Ok, the equation is:
\[\frac{x^2-16}{x^2-4x-12}\]
Step 1: Factor the bottom, because anything divided by zero is undefined.
\[\frac{x^2-16}{(x-6)(x+2)}\]
when x=6 this becomes
\[\frac{x^2-16}{(6-6)(x+2)}\to\frac{x^2-16}{(0)(x+2)}\to\frac{x^2-16}{0}\to \emptyset. \]
when x = -2 the process repeats. Therefore when you factor a denominator, the zeros for that denominator tell you when that function is undefined.