Trong mặt phẳng với hệ trục tọa độ
Cho hai đường thẳng
và
lần lượt có phương trình:
và
, điểm
Phép vị tự tâm
tỉ số
biến đường thẳng
thành
khi đó giá trị của
là
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20192515852212345251/obj20192515852212345251345251_images/obj20192515852212345251345251_img1.png)
![img2](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20192515852212345251/obj20192515852212345251345251_images/obj20192515852212345251345251_img2.png)
![img3](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20192515852212345251/obj20192515852212345251345251_images/obj20192515852212345251345251_img3.png)
![img4](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20192515852212345251/obj20192515852212345251345251_images/obj20192515852212345251345251_img4.png)
![img5](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20192515852212345251/obj20192515852212345251345251_images/obj20192515852212345251345251_img5.png)
![img6](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20192515852212345251/obj20192515852212345251345251_images/obj20192515852212345251345251_img6.png)
![img7](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20192515852212345251/obj20192515852212345251345251_images/obj20192515852212345251345251_img7.png)
![img8](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20192515852212345251/obj20192515852212345251345251_images/obj20192515852212345251345251_img8.png)
![img9](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20192515852212345251/obj20192515852212345251345251_images/obj20192515852212345251345251_img9.png)
![img10](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20192515852212345251/obj20192515852212345251345251_images/obj20192515852212345251345251_img10.png)
![img11](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20192515852212345251/obj20192515852212345251345251_images/obj20192515852212345251345251_img11.png)
A.
1
B.
2
C.
3
D.
4
Đáp án và lời giải
Đáp án:D
Lời giải:
Chọn D Ta lấy điểm Khi đó
Mà