Kết quả của căn {x + 4}  + căn {x + 9}  - 5} / x là

Chọn D

              Ta có \(\mathop {\lim }\limits_{x \to 0} \frac{{\sqrt {x + 4} + \sqrt {x + 9} - 5}}{x} = \mathop {\lim }\limits_{x \to 0} \frac{{\sqrt {x + 4} - 2 + \sqrt {x + 9} - 3}}{x}\)

              \(\begin{array}{l} = \mathop {\lim }\limits_{x \to 0} \frac{{\sqrt {x + 4} - 2}}{x} + = \mathop {\lim }\limits_{x \to 0} \frac{{\sqrt {x + 9} - 3}}{x}\\ = \mathop {\lim }\limits_{x \to 0} \frac{1}{{\sqrt {x + 4} + 2}} + = \mathop {\lim }\limits_{x \to 0} \frac{1}{{\sqrt {x + 9} - 3}} = \frac{1}{4} + \frac{1}{6} = \frac{5}{{12}}\end{array}\)