Tính \(\mathop {\lim }\limits_{x \to 3} \frac{{{x^2} + x - 12}}{{x - 3}}\). Kết quả đúg là:

* Hướng dẫn giải

\(\begin{array}{l}\mathop {\lim }\limits_{x \to 3} \frac{{{x^2} + x - 12}}{{x - 3}}\\ = \mathop {\lim }\limits_{x \to 3} \frac{{\left( {x - 3} \right)\left( {x + 4} \right)}}{{x - 3}}\\ = \mathop {\lim }\limits_{x \to 3} \left( {x + 4} \right) = 7\end{array}\).