What real values of x are not in the domain of $f(x) = \frac{1}{|x^2 + 3x - 4| + |x^2 + 9x - 10|}$?
\(f (x) = {1\over |(x-1) (x+4)+|(x-1)(x+10)|}\)
if x = 1, then
\(f(x) = {1 \over0}\)
f(x) is undefined, when x = 1.
