A person who make friend with you through letters is call a penpal

chỗ cần điền là penpal

Đề bài là gì bạn?

đây bạn

Câu 1: 

1:A

2:C

Câu 1:

3:D

4:C

a, \(P=\left(\sqrt{x}-\dfrac{x+2}{\sqrt{x}+1}\right):\left(\dfrac{\sqrt{x}}{\sqrt{x}+1}-\dfrac{\sqrt{x}-4}{1-x}\right)\)

\(=\left(\dfrac{x+\sqrt{x}}{\sqrt{x}+1}-\dfrac{x+2}{\sqrt{x}+1}\right):\left[\dfrac{\sqrt{x}\left(\sqrt{x}-1\right)}{\left(\sqrt{x}+1\right)\left(\sqrt{x}-1\right)}+\dfrac{\sqrt{x}-4}{\left(\sqrt{x}+1\right)\left(\sqrt{x}-1\right)}\right]\)

\(=\dfrac{\sqrt{x}-2}{\sqrt{x}+1}:\dfrac{x-4}{\left(\sqrt{x}+1\right)\left(\sqrt{x}-1\right)}\)

\(=\dfrac{\sqrt{x}-2}{\sqrt{x}+1}.\dfrac{\left(\sqrt{x}+1\right)\left(\sqrt{x}-1\right)}{\left(\sqrt{x}+2\right)\left(\sqrt{x}-2\right)}\)

\(=\dfrac{\sqrt{x}-1}{\sqrt{x}+2}\)

b, \(P< \dfrac{1}{2}\Leftrightarrow\dfrac{\sqrt{x}-1}{\sqrt{x}+2}< \dfrac{1}{2}\)

\(\Leftrightarrow2\sqrt{x}-2< \sqrt{x}+2\)

\(\Leftrightarrow\sqrt{x}< 4\)

\(\Leftrightarrow0\le x< 16\)

Vậy \(0\le x< 16;x\ne1;x\ne4\).

|x+1|-x+2=3-x

|x+1|       = 3 - x - 2 + x 

|x+1|       = 1

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

Vậy x \(\in\left\{0;-2\right\}\)

Hok tốt !

\(|x+1|-x+2=3-x\)

\(\Leftrightarrow|x+1|-x+2-3+x=0\)

\(\Leftrightarrow|x+1|-1=0\)

\(\Leftrightarrow|x+1|=1\)

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

a=5k+1

Cho \(0\le5k+1\le100\)

=> \(0\le k\le19\)

Có 20 giá trị của k => A có 20 phần tử

Cảm ơn nha.

III. Choose the word or phrase that best complete each sentence.

1. Don’t touch that dog. It _________ bite you.

       A. will                              B. was going to                     C. is going to             D. be going to

2. John paid $ 2 for his meal, _________ he thought it would cost.

            A. less as                    B. not many as                      C. not so much as     D. not as much

3.He was offered the job _________ his qualifications were poor.

A. despite                  B. in spite                  C. even though          D. whereas

4. English is learned by millions of students _________ its importance.

       A. because of                  B. because                             C. despite                   D. although

5. Would you like to stay at home _________ go out?

     A. or                                  B. but playing                       C. and            D. if

6. Will you _________ making models in the future?

     A. pick up                         B. look for                             C. take up                  D. find

7. Is there anything good _________TV tonight?

   A. on                                    B. in                                        C. near                        D. at

8. My mother doesn’t like coffee and _________.

  A. neither do I                     B. neither I do                       C. either do I                         D. I don’t too

9. Can you wait _________ please?

  A. out                                   B. out of                                 C. outside                  D. for

10. _________ the next turning on the right, the post office is in front of you.

  A. Go                                    B. Make                                 C. See                         D. Take

11. We often read the instructions carefully in order to make _________of the things we like best.

  A. meanings                        B. models                               C. copies                    D. uses

12. This orange tastes _________.

  A. sweetly                            B. sweety                               C. sweet                     D. sweets

13. You need to be _________ to follow eggshell carving because it may take two weeks to

    complete one shell.

  A. careful                             B. interesting                         C. fit                            D. patient

14. If you choose sewing as your hobby, you will _________ your own clothes.

  A. do                                     B. make                                  C. take                                    D. get

15. There are many _________ why it is important to have a hobby.

            A. answers                 B. reasons                              C. details                    D. facts

III. Choose the word or phrase that best complete each sentence.

1. Don’t touch that dog. It _________ bite you.

       A. will                              B. was going to                     C. is going to             D. be going to

2. John paid $ 2 for his meal, _________ he thought it would cost.

            A. less as                    B. not many as                      C. not so much as     D. not as much

3.He was offered the job _________ his qualifications were poor.

A. despite                  B. in spite                  C. even though          D. whereas

4. English is learned by millions of students _________ its importance.

       A. because of                  B. because                             C. despite                   D. although

5. Would you like to stay at home _________ go out?

     A. or                                  B. but playing                       C. and            D. if

6. Will you _________ making models in the future?

     A. pick up                         B. look for                             C. take up                  D. find

7. Is there anything good _________TV tonight?

   A. on                                    B. in                                        C. near                        D. at

8. My mother doesn’t like coffee and _________.

  A. neither do I                     B. neither I do                       C. either do I                         D. I don’t too

9. Can you wait _________ please?

  A. out                                   B. out of                                 C. outside                  D. for

10. _________ the next turning on the right, the post office is in front of you.

  A. Go                                    B. Make                                 C. See                         D. Take

11. We often read the instructions carefully in order to make _________of the things we like best.

  A. meanings                        B. models                               C. copies                    D. uses

12. This orange tastes _________.

  A. sweetly                            B. sweety                               C. sweet                     D. sweets

13. You need to be _________ to follow eggshell carving because it may take two weeks to

    complete one shell.

  A. careful                             B. interesting                         C. fit                            D. patient

14. If you choose sewing as your hobby, you will _________ your own clothes.

  A. do                                     B. make                                  C. take                                    D. get

15. There are many _________ why it is important to have a hobby.

            A. answers                 B. reasons                              C. details                    D. facts

Chúc em học tốt

Rewrite the sentence ,use the word in parentheses:

There are two fridges,a table,four chairs in Thuong's  kitchen. - ............Thuong's kitchen has 2 fridges, a table,  four chairs..............

=> Thuong's kitchen has two fridges , a table , four chairs .