Tính giới hạn lim (x -> - 1) (x + 1)/(- 4x^2 - x + 3).

Ta có \(\mathop {\lim }\limits_{x \to - 1} \frac{{x + 1}}{{ - 4{x^2} - x + 3}} = \mathop {\lim }\limits_{x \to - 1} \frac{{x + 1}}{{\left( {x + 1} \right)\left( { - 4x + 3} \right)}} = \mathop {\lim }\limits_{x \to - 1} \frac{1}{{ - 4x + 3}} = \frac{1}{{ - 4 \cdot \left( { - 1} \right) + 3}} = \frac{1}{7}\).