Cho khai triển ![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20194131752219504903/obj20194131752219504903594020_images/obj20194131752219504903594020_img1.png)
,
. tìm số giá trị nguyên của
với
sao cho tồn tại
thỏa mãn
.
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20194131752219504903/obj20194131752219504903594020_images/obj20194131752219504903594020_img1.png)
![img2](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20194131752219504903/obj20194131752219504903594020_images/obj20194131752219504903594020_img2.png)
![img3](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20194131752219504903/obj20194131752219504903594020_images/obj20194131752219504903594020_img3.png)
![img4](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20194131752219504903/obj20194131752219504903594020_images/obj20194131752219504903594020_img4.png)
![img5](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20194131752219504903/obj20194131752219504903594020_images/obj20194131752219504903594020_img5.png)
![img6](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20194131752219504903/obj20194131752219504903594020_images/obj20194131752219504903594020_img6.png)
![img7](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20194131752219504903/obj20194131752219504903594020_images/obj20194131752219504903594020_img7.png)
![img8](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20194131752219504903/obj20194131752219504903594020_images/obj20194131752219504903594020_img8.png)
![img9](https://cungthi.online/upload/questionbank3_20201220/eduquestion/20194131752219504903/obj20194131752219504903594020_images/obj20194131752219504903594020_img9.png)
A.
B.
C.
D.
Đáp án và lời giải
Đáp án:B
Lời giải:
Phân tích: Ta có khai triển
. Từ giả thiết ta có
,
. Suy ra
. Do
nên
chia cho 3 phải dư 2, suy ra
với
. Mà
nên
từ đó suy ra
. Vậy có
số giá trị nguyên của
với
thỏa mãn ycbt.
Đáp án đúng là B