Hi! My name is Ben. I'm 12 years old. I'm very helpful. I usually wash clothes and clean the rooms at home. I always help my teachers at school. And I am a foodie(吃货)，I like ice creams. They are sweet. And potatoes are my favourite vegetables. I like fruits, but I don't like bananas.

    I'm a cool boy，too. I like playing ping-pong，football and I can swim very well. I was afraid of dogs before，but now I have a pet dog. It drinks orange juice every day. It can play with a ball, it's so cute. I like it very much.

    What am I going to be? Mm…I want to be a police officer. Because helping people is fun for me. I will study hard and do more exercise.

若函数$f\left(x\right)=x^2+ax+b$有两个不同的零点$x_1,x_2$，且$1<x_1<x_2<3$，那么在$f\left(x_1\right),f\left(x_2\right)$两个函数值中               (     )           

若函数y=a $x^{a^2-2a-6}$是二次函数且图象开口向上，则a=（　　）

已知双曲线$\frac{x^2}{a^2}-\frac{y^2}{b^2}$=1（a＞0，b＞0）的右焦点到左顶点的距离等于它到渐近线距离的2倍，则其渐近线方程为（　　）