Cho hai số phức
và
với
và
có phần ảo bằng 7. Tính
.
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019431777329652760/obj2019431777329652760740466_images/obj2019431777329652760740466_img1.png)
![img2](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019431777329652760/obj2019431777329652760740466_images/obj2019431777329652760740466_img2.png)
![img3](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019431777329652760/obj2019431777329652760740466_images/obj2019431777329652760740466_img3.png)
![img4](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019431777329652760/obj2019431777329652760740466_images/obj2019431777329652760740466_img4.png)
![img5](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2019431777329652760/obj2019431777329652760740466_images/obj2019431777329652760740466_img5.png)
A.
B.
C.
D.
Đáp án và lời giải
Đáp án:D
Lời giải:
Vậy đáp án đúng là D.