Hypebol 3x

C

- Hướng dẫn giải

Chọn C.

Ta có: $3x^2-y^2=12 \Rightarrow \frac{x^2}{4}-\frac{y^2}{12}=1$

$\left[\begin{array}{c}{a}^2=4\\ b^2=12\\ c^2=a^2+b^2\end{array}\right.$$\Rightarrow$$\left[\begin{array}{c}a=2\\ b=2\sqrt{3}\\ c=4\end{array}\right.$

=> $e=\frac{c}{a}=2$