Với giá trị nào của m thì bất phương trình sau vô nghiệm:
A. A.
.
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2020591573739354623/obj2020591573739354623642498_images/obj2020591573739354623642498_img1.png)
B. B.
.
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2020591573739354623/obj2020591573739354623806335_images/obj2020591573739354623806335_img1.png)
C. C.
.
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2020591573739354623/obj2020591573739354623285773_images/obj2020591573739354623285773_img1.png)
D. D.
.
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2020591573739354623/obj2020591573739354623130672_images/obj2020591573739354623130672_img1.png)
Đáp án và lời giải
Đáp án:A
Lời giải: Lời giải
PT
Bât phương trình
vô nghiệm khi và chỉ khi
Kết luận:
.
![img1](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2020591573739354623/obj2020591573739354623802405_images/obj2020591573739354623802405_img1.png)
![img2](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2020591573739354623/obj2020591573739354623802405_images/obj2020591573739354623802405_img2.png)
![img3](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2020591573739354623/obj2020591573739354623802405_images/obj2020591573739354623802405_img3.png)
![img4](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2020591573739354623/obj2020591573739354623802405_images/obj2020591573739354623802405_img4.png)
![img5](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2020591573739354623/obj2020591573739354623802405_images/obj2020591573739354623802405_img5.png)
![img6](https://cungthi.online/upload/questionbank3_20201220/eduquestion/2020591573739354623/obj2020591573739354623802405_images/obj2020591573739354623802405_img6.png)