\(\mathop {\lim }\limits_{x \to  + \infty } \frac{{2{x^4} + 3{x^3} - 2{x^2} - 7}}{{x - 2{x^4}}}\) bằng:

* Hướng dẫn giải

\(\mathop {\lim }\limits_{x \to  + \infty } \frac{{2{x^4} + 3{x^3} - 2{x^2} - 7}}{{x - 2{x^4}}} = \mathop {\lim }\limits_{x \to  + \infty } \frac{{{x^4}\left( {2 + \frac{3}{x} - \frac{2}{{{x^2}}} - \frac{7}{{{x^4}}}} \right)}}{{{x^4}\left( {\frac{1}{{{x^3}}} - 2} \right)}} = \mathop {\lim }\limits_{x \to  + \infty } \frac{{2 + \frac{3}{x} - \frac{2}{{{x^2}}} - \frac{7}{{{x^4}}}}}{{\frac{1}{{{x^3}}} - 2}} =  - 1\)