Đặt a=3√16x-24; b=3√1-3x; c=3√19x-25
Ta có: b3 +c3=1-3x+19x-25=a3
Ta lại có: a=b+c
=>a3=b3 +c3+3bc(b+c)
0=3bc(b+c)
0=bc(b+c)
=> b=0 hoặc c=0 hoặc b+c=0sau đó tính tiếp :v
Các câu hỏi tương tự
Chọn đáp án đúng A, B, C hoặc D cho những câu sau
What are you going.......... tomorrow?
A. to do
B. do
C. did
D. doing
Match the words that have opposite meaning:
1. old 2. small3. far4. short5. early6. city7. quiet
a. tallb. countrysidec. noisyd. neare. largef. lateg. modern
1.2.3.4.5.6.7.
Đọc tiếp
Match the words that have opposite meaning:
1. old 2. small 3. far 4. short 5. early 6. city 7. quiet |
a. tall b. countryside c. noisy d. near e. large f. late g. modern |
1. 2. 3. 4. 5. 6. 7. |
Đọc đoạn văn và khoanh tròn vào đáp án A, B, C, hoặc D thích hợp để điền vào chỗ trống trong đoạn văn.Tony and his friends (1) ...............have a trip to Vietnam next summer. At first, they are going to Hanoi (2) ................plane and they are going to stay there in two days. Then they are going to travel to Ha Long and Hue. They are going to visit a (3) .......................of places of interest and some primary schools in Hanoi. They are going to (4) .................. students in the...
Đọc tiếp
Đọc đoạn văn và khoanh tròn vào đáp án A, B, C, hoặc D thích hợp để điền vào chỗ trống trong đoạn văn.
Tony and his friends (1) ...............have a trip to Vietnam next summer. At first, they are going to Hanoi (2) ................plane and they are going to stay there in two days. Then they are going to travel to Ha Long and Hue. They are going to visit a (3) .......................of places of interest and some primary schools in Hanoi. They are going to (4) .................. students in the schools practice speaking English. Finally, they are going to fly back to England (5).............Hanoi.
Question 3
A. many
B. some
C. few
D. lot
Read and match.1. Don’t play with the matches! A. You may fall off the swing.2. Don’t swing too fast! B. You may get a burn.3. Don’t play with the knife! C. It may bite you.4. Don’t play with a strange dog! D. You may get a cut.
Đọc tiếp
Read and match.
1. Don’t play with the matches! A. You may fall off the swing.
2. Don’t swing too fast! B. You may get a burn.
3. Don’t play with the knife! C. It may bite you.
4. Don’t play with a strange dog! D. You may get a cut.
Đọc đoạn văn và khoanh tròn vào đáp án A, B, C, hoặc D thích hợp để điền vào chỗ trống trong đoạn văn.Tony and his friends (1) ...............have a trip to Vietnam next summer. At first, they are going to Hanoi (2) ................plane and they are going to stay there in two days. Then they are going to travel to Ha Long and Hue. They are going to visit a (3) .......................of places of interest and some primary schools in Hanoi. They are going to (4) .................. students in the...
Đọc tiếp
Đọc đoạn văn và khoanh tròn vào đáp án A, B, C, hoặc D thích hợp để điền vào chỗ trống trong đoạn văn.
Tony and his friends (1) ...............have a trip to Vietnam next summer. At first, they are going to Hanoi (2) ................plane and they are going to stay there in two days. Then they are going to travel to Ha Long and Hue. They are going to visit a (3) .......................of places of interest and some primary schools in Hanoi. They are going to (4) .................. students in the schools practice speaking English. Finally, they are going to fly back to England (5).............Hanoi.
A. is going
B. are to
C. are going to
Đọc đoạn văn và khoanh tròn vào đáp án A, B, C, hoặc D thích hợp để điền vào chỗ trống trong đoạn văn.Tony and his friends (1) ...............have a trip to Vietnam next summer. At first, they are going to Hanoi (2) ................plane and they are going to stay there in two days. Then they are going to travel to Ha Long and Hue. They are going to visit a (3) .......................of places of interest and some primary schools in Hanoi. They are going to (4) .................. students in the...
Đọc tiếp
Đọc đoạn văn và khoanh tròn vào đáp án A, B, C, hoặc D thích hợp để điền vào chỗ trống trong đoạn văn.
Tony and his friends (1) ...............have a trip to Vietnam next summer. At first, they are going to Hanoi (2) ................plane and they are going to stay there in two days. Then they are going to travel to Ha Long and Hue. They are going to visit a (3) .......................of places of interest and some primary schools in Hanoi. They are going to (4) .................. students in the schools practice speaking English. Finally, they are going to fly back to England (5).............Hanoi.
Question 2
A. to
B. by
C. with
D. for
Đọc đoạn văn và khoanh tròn vào đáp án A, B, C, hoặc D thích hợp để điền vào chỗ trống trong đoạn văn.Tony and his friends (1) ...............have a trip to Vietnam next summer. At first, they are going to Hanoi (2) ................plane and they are going to stay there in two days. Then they are going to travel to Ha Long and Hue. They are going to visit a (3) .......................of places of interest and some primary schools in Hanoi. They are going to (4) .................. students in the...
Đọc tiếp
Đọc đoạn văn và khoanh tròn vào đáp án A, B, C, hoặc D thích hợp để điền vào chỗ trống trong đoạn văn.
Tony and his friends (1) ...............have a trip to Vietnam next summer. At first, they are going to Hanoi (2) ................plane and they are going to stay there in two days. Then they are going to travel to Ha Long and Hue. They are going to visit a (3) .......................of places of interest and some primary schools in Hanoi. They are going to (4) .................. students in the schools practice speaking English. Finally, they are going to fly back to England (5).............Hanoi.
Question 4
A. help
B. visit
C. ask
D. go
Đọc đoạn văn và khoanh tròn vào đáp án A, B, C, hoặc D thích hợp để điền vào chỗ trống trong đoạn văn.Tony and his friends (1) ...............have a trip to Vietnam next summer. At first, they are going to Hanoi (2) ................plane and they are going to stay there in two days. Then they are going to travel to Ha Long and Hue. They are going to visit a (3) .......................of places of interest and some primary schools in Hanoi. They are going to (4) .................. students in the...
Đọc tiếp
Đọc đoạn văn và khoanh tròn vào đáp án A, B, C, hoặc D thích hợp để điền vào chỗ trống trong đoạn văn.
Tony and his friends (1) ...............have a trip to Vietnam next summer. At first, they are going to Hanoi (2) ................plane and they are going to stay there in two days. Then they are going to travel to Ha Long and Hue. They are going to visit a (3) .......................of places of interest and some primary schools in Hanoi. They are going to (4) .................. students in the schools practice speaking English. Finally, they are going to fly back to England (5).............Hanoi.
Question 5
A. to
B. from
C. for
D. on
Match the sentences
1. What’s your address?
a. I always do morning exercise
2. What’s the village like?
b. twice a week
3. What do you do in the morning?
c. It’s small and quiet
4. How often do you have English?
d. It’s 81 Tran Hung Dao Street
Đọc tiếp
Match the sentences
1. What’s your address? |
a. I always do morning exercise |
2. What’s the village like? |
b. twice a week |
3. What do you do in the morning? |
c. It’s small and quiet |
4. How often do you have English? |
d. It’s 81 Tran Hung Dao Street |