Tìm giới hạn Lim {3 -căn {3 - 2x / x^2} + 4x + 3

Chọn C

\[\begin{array}{l}\mathop {\lim }\limits_{x \to - 3} \frac{{3 - \sqrt {3 - 2x} }}{{{x^2} + 4x + 3}} = \mathop {\lim }\limits_{x \to - 3} \frac{{\left( {3 - \sqrt {3 - 2x} } \right)\left( {3 + \sqrt {3 - 2x} } \right)}}{{\left( {x + 1} \right)\left( {x + 3} \right)\left( {3 + \sqrt {3 - 2x} } \right)}} = \mathop {\lim }\limits_{x \to - 3} \frac{{6 + 2x}}{{\left( {x + 1} \right)\left( {x + 3} \right)\left( {3 + \sqrt {3 - 2x} } \right)}}\\ = \mathop {\lim }\limits_{x \to - 3} \frac{2}{{\left( {x + 1} \right)\left( {3 + \sqrt {3 - 2x} } \right)}} = \frac{2}{{\left( { - 3 + 1} \right)\left( {3 + \sqrt {3 - 2.( - 3)} } \right)}} = - \frac{1}{6}\end{array}\]