Giá trị \(\mathop {\lim }\limits_{x \to 1} \dfrac{{{x^2} - 3x + 2}}{{{x^2} - 1}}\) bằng:

* Hướng dẫn giải

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

Chọn A.