SoluciĆ³n

Utilizando la propiedad de la raiz: $1$

$$\mathop {\lim }\limits_{x \to - 2} \sqrt {{x^2} - 6x + 3} = \sqrt {\mathop {\lim }\limits_{x \to - 2} \left( {{x^2} - 6x + 3} \right)} = \sqrt {19} $$