với x ≥ -1.

a) Rút gọn biểu thức B;

b) Tìm x sao cho B có giá trị là 16.

Giải chi tiết các bước hộ mình với ạ!!!

có tổng bằng 35 là 17+18=35

có tổng là 61 là 30+31=61

mình làm ngắn gọn thôi nha!!!

I. Combine each pair of sentences, use “ too… or enough …”

1) Jane isn’t old. She can’t drive a car.

2) The question is very easy. Every one can answer it. 

3) Tom wasn’t strong. He couldn’t lift the heavy box. 

4) The cartoon is quite interesting. Children can enjoy it.

5) The test is very easy. We can do it in ten minutes. 

6) She is clever. She can make beautiful dresses. 

7) She’s very young. She can’t get married. 

8) The man is very old. He can’t walk alone. 

9) Those clothes are small. I can’t wear them.

10) The test is very difficult. He can’t finish it on time.

II. Rewrite the following sentences.

1) Do you want to come and watch Harry Potter with me? (Begin with 

“Would you like”)

2) Could you explain this question to me? (Begin with “Would you mind”)

3) Is it all right if I take a photo? (Begin with “Would you mind”)

4) It’s not easy to answer these questions. (Begin with “To answer”)

5) The test is difficult to do in fifteen minutes. (Begin with “It’s”)

6) To understand what he is speaking is not easy.(Begin with “It’s”)

7) This question is difficult to understand. (Begin with “It’s”)

8) Travelling around the town by bike is exciting.(Begin with “It’s”)

9) Would you mind helping me with the washing? (Begin with “Would 

you please”)

10) Do you mind if I smoke? (Begin with “Would you mind”)

11) Would you please clean the floor for me? (Begin with “Would you mind”)

12) Shall I sit here? (Begin with “Do you mind”)

13) Would you mind if I took some photos? (Begin with “Do you mind”)

14) Do you want me to come to the airport with you? (Begin with “Shall”)

I. Combine each pair of sentences, using the given words.

1) Lan couldn’t  go to school yesterday. She was sick. (so)

2) The lesson was difficult. They didn’t understand it. (such…that)

3) The film was very interesting.We wanted to see it  again.(so…that)

4) The weather was very hot. We couldn’t sleep well. (too)

5) The exercise is so easy.We can do it in ten minutes.(enough) 

6) She is very kind. Everybody likes her. (so…that) 

7) They are bad students. They can’t do any exercise. (such…that)

8) She did the test very well. It was very difficult. (but)

II. Rewrite the sentences, using the words provided.

1) You should study harder on your examination. (I suggest that)

2) They have had the lesson explained. (Active causative form)

3) It took us two hours to water the flowers. (S + spend)

4) Lan couldn’t go to the club because of her illness. (so)

5) Despite the heaviness of the suitcase, he can carry it. (although)

6) Because of the heavy rain, we couldn’t go on a picnic. (because)

7) The food is delicious enough for her to eat a lot. (such…that)

8) It was such hot water that he couldn’t drink it. (so…that)

9) The shirt is too small for me to wear. (enough)

10) The exercise is so difficult that we can’t do it. (too)

11) The film is interesting enough for us to watch many times. (such…that)

12) Because he was lazy, he failed in the exam. (because of)

13) Although the test was long, he finished the test on time. (despite)

14) Nam didn’t go  to school on time because he got up late. (since)

15) I spend an hour travelling to work by motorbike.  (It take)

16) He will have someone repair his computer. (Passive causative form)

17) Jane got wet because she forgot her umbrella. (so)

18) You must learn very hard so that you can pass the exam. (for)

cho 8.8 g một hỗn hợp Mg và MgO tác dụng vừa đủ với dung dịch HCl 7.3% thì thu được 4.48 lít khí

a)Viết pthh của các phản ứng xảy ra

b)Tính thành phần phần trăm về khối lượng mỗi chất trong hỗn hợp ban đầu

c)Tính khối lượng dung dịch HCl đã dùng

d)Tính nồng đồ phần trăm dung dịch thu được