Xác định mathop lim limits_x to left( - 1 right) - fracx2 + 3x + 2left| x + 1

Khi $x \to {\left( { - 1} \right)^ - } \Rightarrow x < - 1 \Rightarrow x + 1 < 0 \Rightarrow \left| {x + 1} \right| = - \left( {x + 1} \right)$
$\begin{array}{l} \mathop {\lim }\limits_{x \to {{\left( { - 1} \right)}^ - }} \frac{{{x^2} + 3x + 2}}{{\left| {x + 1} \right|}} = \mathop {\lim }\limits_{x \to {{\left( { - 1} \right)}^ - }} \frac{{{x^2} + 3x + 2}}{{ - \left( {x + 1} \right)}}\\ = \mathop {\lim }\limits_{x \to {{\left( { - 1} \right)}^ - }} \frac{{\left( {x + 1} \right)\left( {x + 2} \right)}}{{ - \left( {x + 1} \right)}} = \mathop {\lim }\limits_{x \to {{\left( { - 1} \right)}^ - }} \left[ { - \left( {x + 2} \right)} \right] = - 1. \end{array}$