Câu 9:
$\lim\dfrac{n^2-\sqrt[3]{n^3+1}+2n}{n\sqrt{n^2+1}+3}$
$=\lim\dfrac{1-\dfrac{\sqrt[3]{1+\dfrac{1}{n^3}}}{n}+\dfrac{2}{n}}{\sqrt{1+\dfrac{1}{n^2}}+\dfrac{3}{n^2}}$
$=\dfrac{1-0+0}{1+0+0}=1$
Câu 10:
$\lim\dfrac{5n-\sqrt{4n^2+1}}{2-n}$
$=\lim\dfrac{5-\sqrt{4+\dfrac{1}{n^2}}}{\dfrac{2}{n}-1}$
$=\dfrac{5-\sqrt{4+0}}{0-1}=-3$