Đề bài

\(\mathop {\lim }\limits_{x \to 3} \frac{{{x^2} - 9}}{{x - 3}}\) bằng: A. 0.                                             B. 6.                                             C. 3.                                              D. 1.

Lời giải chi tiết

\(\mathop {\lim }\limits_{x \to 3} \frac{{{x^2} - 9}}{{x - 3}} = \mathop {\lim }\limits_{x \to 3} \frac{{\left( {x - 3} \right)\left( {x + 3} \right)}}{{x - 3}} = \mathop {\lim }\limits_{x \to 3} \left( {x + 3} \right) = 3 + 3 = 6\)Chọn B.