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1. I'm not sure. I........................come a few minutes late. A. may B. must C. mustn't D. needn't 2. Bring your umbrella. It..................rain later today. A. must B. may C. mustn't D. needn't 3. ''What are you doing this weekend?'' ''I haven't decided yet. I................go on a picnic with my family''. A. may B. may not C. must D. needn't 4. ''I didn't have time for breakfast this morning.'' ''You.............be very hungry now.'' A. might B. may C. mustn't D. must 5....
Đọc tiếp

1. I'm not sure. I........................come a few minutes late.

A. may B. must C. mustn't D. needn't

2. Bring your umbrella. It..................rain later today.

A. must B. may C. mustn't D. needn't

3. ''What are you doing this weekend?''

''I haven't decided yet. I................go on a picnic with my family''.

A. may B. may not C. must D. needn't

4. ''I didn't have time for breakfast this morning.''

''You.............be very hungry now.''

A. might B. may C. mustn't D. must

5. It's quite urgent. You........type the reports today.

A. must B. might C. needn't D. would

6. Don't worry if you're a minute or two late. We..........be exactly on time for the meeting.

A. must B. mustn't C. needn't D. may

7. Jane's glasses are on the desk, so she.......be here.

A. must B. shall C. ought D. will

8. The gas tank is almost empty. We...........stop at the next service station.

A. mustn't B. might C. needn't D. had better

9. A person........eat in order to live.

A. have to B. must C. should D. may

10. A person........eat a balanced diet.

A. should B. ought C. may D. must

11. I don't have onough money to take the bus, so I............walk home.

A. should B. mustn't C. have to D. needn't

12. You.........eat these mushrooms. They are very poisonous.

A. needn't B. can't C. mustn't D. won't

13. I can't find my umbrella. I........it in the restaurant last night.

A. must have left B. had left C. left D. might leave

14. I had a test this morning. I didn't do it well. I........last night.

A. should study B. must have studied C. should have studied D. must study

15. Tom goes to school very often, but he was absent yesterday. He..............ill

A. must be B. must have been C. might be D. might have been.

1
1 tháng 11 2018

1. I'm not sure. I........................come a few minutes late.

A. may B. must C. mustn't D. needn't

2. Bring your umbrella. It..................rain later today.

A. must B. may C. mustn't D. needn't

3. ''What are you doing this weekend?''

''I haven't decided yet. I................go on a picnic with my family''.

A. may B. may not C. must D. needn't

4. ''I didn't have time for breakfast this morning.''

''You.............be very hungry now.''

A. might B. may C. mustn't D. must

5. It's quite urgent. You........type the reports today.

A. must B. might C. needn't D. would

6. Don't worry if you're a minute or two late. We..........be exactly on time for the meeting.

A. must B. mustn't C. needn't D. may

7. Jane's glasses are on the desk, so she.......be here.

A. must B. shall C. ought D. will

8. The gas tank is almost empty. We...........stop at the next service station.

A. mustn't B. might C. needn't D. had better

9. A person........eat in order to live.

A. have to B. must C. should D. may

10. A person........eat a balanced diet.

A. should B. ought C. may D. must

11. I don't have onough money to take the bus, so I............walk home.

A. should B. mustn't C. have to D. needn't

12. You.........eat these mushrooms. They are very poisonous.

A. needn't B. can't C. mustn't D. won't

13. I can't find my umbrella. I........it in the restaurant last night.

A. must have left B. had left C. left D. might leave

14. I had a test this morning. I didn't do it well. I........last night.

A. should study B. must have studied C. should have studied D. must study

15. Tom goes to school very often, but he was absent yesterday. He..............ill

A. must be B. must have been C. might be D. might have been.

13 tháng 12 2017

\(\dfrac{1}{1-x}\)+\(\dfrac{1}{1+x}\)+\(\dfrac{2}{1+x^2}\)+\(\dfrac{4}{1+x^4}\)+\(\dfrac{8}{1+x^8}\)+\(\dfrac{16}{1+x^{16}}\)

=

=\(\dfrac{4}{1-x^4}\)+\(\dfrac{4}{1+x^4}\)+\(\dfrac{8}{1+x^8}\)+\(\dfrac{16}{1+x^{16}}\)

=\(\dfrac{8}{1-x^8}\)+\(\dfrac{8}{1+x^8}\)+\(\dfrac{16}{1+x^{16}}\)

=\(\dfrac{16}{1-x^{16}}\)+\(\dfrac{16}{1+x^{16}}\)

=\(\dfrac{32}{1-x^{32}}\)

8 tháng 8 2015

a) Ta có I 2x - 1 I = 2015

=> 2x-1=2015 hoặc 2x-1=2015

+,Th1: 2x-1=2015

             2x=2015+1

             2x=2016

              x=2016:2

             x=1008

+,Th2: 2x-1=-2015

              2x=-2015+1

             2x=-2014

              x=-2014:2

             x=-1007

Vậy x=1008, x=-1007

 

 

|x-1|<5

th1: x-1<5=> x<6

th2: x-1<-5=> x<-4

vậy x <6 hoặc<-4

|x-1|>5 cũng tương tự như thế

còn mấy câu khác Nguyễn Diệu Thảo làm thế chắc bạn cũng biết cách làm rồi

L_I_K_E CHO MÌNH NHA!!!

a) Chương trình bị lỗi

b) Chương trình bị lỗi

c) Chương trình bị lỗi luôn

26 tháng 7 2019

I I  là dấu giá trị tuyệt đối nhé

26 tháng 7 2019

|7 + 5x| = 1 - 4x

=> \(\orbr{\begin{cases}7+5x=1-4x\left(đk:x\le\frac{1}{4}\right)\\7+5x=4x-1\left(đk:x\ge\frac{1}{4}\right)\end{cases}}\)

=> \(\orbr{\begin{cases}7-1=-4x-5x\\7+1=4x-5x\end{cases}}\)

=> \(\orbr{\begin{cases}6=-9x\\8=-x\end{cases}}\)

=> \(\orbr{\begin{cases}x=-\frac{2}{3}\left(tm\right)\\x=-8\left(ktm\right)\end{cases}}\)

|4x- 2x| + 1 = 2x

=> |4x2 - 2x| = 2x - 1

=> \(\orbr{\begin{cases}4x^2-2x=2x-1\left(đk:x\ge\frac{1}{2}\right)\\4x^2-2x=1-2x\left(đk:x\le\frac{1}{2}\right)\end{cases}}\)

=> \(\orbr{\begin{cases}4x^2-2x-2x+1=0\\4x^2-2x-1+2x=0\end{cases}}\)

=> \(\orbr{\begin{cases}\left(2x-1\right)^2=0\\4x^2-1=0\end{cases}}\)

=> \(\orbr{\begin{cases}2x-1=0\\x^2=\frac{1}{4}\end{cases}}\)

=> \(\orbr{\begin{cases}x=\frac{1}{2}\\x=\pm\frac{1}{2}\end{cases}}\)(tm)

Vậy ...

31 tháng 8 2023

???

6 tháng 4 2019

#It's the moment when you're in good mood, you accidentally click back =.=

1) Calculate

\(P=1\frac{1}{3}.1\frac{1}{8}.1\frac{1}{15}....1\frac{1}{63}.1\frac{1}{80}\)

\(=\frac{4}{3}.\frac{9}{8}.\frac{16}{15}....\frac{64}{63}.\frac{81}{80}\)

\(=\frac{2.2}{1.3}.\frac{3.3}{2.4}.\frac{4.4}{3.5}....\frac{8.8}{7.9}.\frac{9.9}{8.10}\)

\(=\frac{2.9}{10}=\frac{9}{5}\)

7 tháng 8 2019

ta có: 10010 + 1 > 10010 - 1

⇒ A = \(\frac{100^{10}+1}{100^{10}-1}< \frac{100^{10}+1-2}{100^{10}-1-2}=\frac{100^{10}-1}{100^{10}-3}=B\)

vậy A < B

19 tháng 12 2015

a) |2x +1| = 7

Th1: 2x + 1 = 7 

<=> x  = 3

Th2: 2x + 1 = -7 

<=> x = -4 

15 tháng 6 2018

\(1)\) Ta có : 

\(\left|2x-1\right|\ge0\)

\(\Leftrightarrow\)\(A=\left|2x-1\right|+8\ge8\)

Dấu "=" xảy ra \(\Leftrightarrow\)\(\left|2x-1\right|=0\)

\(\Leftrightarrow\)\(2x-1=0\)

\(\Leftrightarrow\)\(2x=1\)

\(\Leftrightarrow\)\(x=\frac{1}{2}\)

Vậy GTNN của \(A\) là \(8\) khi \(x=\frac{1}{2}\)

Chúc bạn học tốt ~ 

15 tháng 6 2018

\(2)\) Ta có : 

\(B=\left|x-3\right|+\left|x-9\right|-1\)

\(B=\left|x-3\right|+\left|9-x\right|-1\ge\left|x-3+9-x\right|-1=\left|6\right|-1=6-1=5\)

Dấu "=" xảy ra khi và chỉ khi \(\left(x-3\right)\left(9-x\right)\ge0\)

Trường hợp 1 : 

\(\hept{\begin{cases}x-3\ge0\\9-x\ge0\end{cases}\Leftrightarrow\hept{\begin{cases}x\ge3\\x\le9\end{cases}\Leftrightarrow}3\le x\le9}\)

Trường hợp 2 : 

\(\hept{\begin{cases}x-3\le0\\9-x\le0\end{cases}\Leftrightarrow\hept{\begin{cases}x\le3\\x\ge9\end{cases}}}\) ( loại ) 

Vậy GTNN của \(B\) là \(5\) khi \(3\le x\le9\)

Chúc bạn học tốt ~