Tính giới hạn Lim {{x^2} + 5x + 6/ x^2} - 4

Ta có:\[\mathop {\lim }\limits_{x \to - 2} \frac{{{x^2} + 5x + 6}}{{{x^2} - 4}} = \mathop {\lim }\limits_{x \to - 2} \frac{{\left( {x + 2} \right)\left( {x + 3} \right)}}{{\left( {x + 2} \right)\left( {x - 2} \right)}}\]\[ = \mathop {\lim }\limits_{x \to - 2} \frac{{x + 3}}{{x - 2}}\]\[ = \frac{{ - 2 + 3}}{{ - 2 - 2}}\]\[ = - \frac{1}{4}\].