Trong mặt phẳng tọa độ
cho điểm
và đường thẳng
. Biết rằng có hai điểm
thuộc
sao cho
. Tổng hoành độ của
là :
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20194615863717332293/obj20194615863717332293477733_images/obj20194615863717332293477733_img1.png)
![img2](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20194615863717332293/obj20194615863717332293477733_images/obj20194615863717332293477733_img2.png)
![img3](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20194615863717332293/obj20194615863717332293477733_images/obj20194615863717332293477733_img3.png)
![img4](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20194615863717332293/obj20194615863717332293477733_images/obj20194615863717332293477733_img4.png)
![img5](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20194615863717332293/obj20194615863717332293477733_images/obj20194615863717332293477733_img5.png)
![img6](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20194615863717332293/obj20194615863717332293477733_images/obj20194615863717332293477733_img6.png)
![img7](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20194615863717332293/obj20194615863717332293477733_images/obj20194615863717332293477733_img7.png)
A.
B.
C.
2
D.
5
Đáp án và lời giải
Đáp án:B
Lời giải:
Phân tích: Gọi Ta có :
Vậy:
Đáp án đúng là B