[tex]7. \frac{x^5+1}{x^3+1}=\frac{(x+1)(x^4-x^3+x^2-x+1)}{(x+1)(x^2-x+1)}=\frac{(x^4-x^3+x^2-x+1)}{(x^2-x+1)}=>lim=\frac{5}{3}[/tex]
[tex]8. \frac{2x^3+6\sqrt{3}}{3-x^2}=\frac{2(x+\sqrt{3})(x^2-\sqrt{3}x+3)}{(\sqrt{3}-x)(\sqrt{3}+x)}=\frac{2(x^2-\sqrt{3}x+3)}{(\sqrt{3}-x)}[/tex]
rồi bạn thế x vào tìm đc lim.
[tex]9.\left | \frac{-x^2-x+6}{x^2+3x} \right |=\left | \frac{-(x-2)(x+3)}{x(x+3)} \right |=\left | \frac{-(x-2)}{x} \right |[/tex]
thế x vào tính đc lim