Đề bài

Tìm các giới hạn sau:

a) $\mathop {\lim }\limits_{x \to  - 3} \left( {8 + 3x - {x^2}} \right)$;

b) $\mathop {\lim }\limits_{x \to 2} \left[ {\left( {5x - 1} \right)\left( {2 - 4x} \right)} \right]$;

c) $\mathop {\lim }\limits_{x \to  - 2} \frac{{{x^2} - x}}{{{{\left( {2x + 1} \right)}^2}}}$;

d) $\mathop {\lim }\limits_{x \to  - 1} \sqrt {10 - 2{x^2}}$.