Chapter 2 - Limits - 2.3 Techniques for Computing Limits - 2.3 Exercises - Page 76: 2

$\lim\limits_{x \to a^{-}}{f(x)} = \lim\limits_{x \to a^{+}}{f(x)}= f(a)$

Real polynomials have R as their domain and they are continuous, so the limit is $\lim\limits_{x \to a^{-}}{f(x)} = \lim\limits_{x \to a^{+}}{f(x)}= f(a)$ (replacing $x$ with the value)