Tính: \(\mathop {\lim }\limits_{x \to - 1} \dfrac{{{x^3} + 2{x^2} - 5x - 6}}{{{x^2} - 2x - 3}}\).

* Hướng dẫn giải

\(\mathop {\lim }\limits_{x \to  - 1} \dfrac{{{x^3} + 2{x^2} - 5x - 6}}{{{x^2} - 2x - 3}} = \mathop {\lim }\limits_{x \to  - 1} \dfrac{{\left( {x + 1} \right)\left( {{x^2} + x - 6} \right)}}{{\left( {x + 1} \right)\left( {x - 3} \right)}}\) \( = \mathop {\lim }\limits_{x \to  - 1} \dfrac{{\left( {{x^2} + x - 6} \right)}}{{\left( {x - 3} \right)}} =   \dfrac{3}{2}\) .

Chọn A.