chia số gạo trên xe thứ nhất thành 3 phần bằng nhau thì số gạo trên xe thứ 2 là 4 phần và số gạo trên xe thứ 3 là 7 phần như thế

Hiệu số phần bằng nhau giưa số gạo chở trên xe thứ 3 và xe thứ 2 là

7-4=3 phần

Giá trị 1 phần là

12:3=4 tấn

Số gạo xe thứ 1 chở là

4x3=12 tấn

Số gạo xe thứ 2 chở là

4x4=16 tấn

Số gạo xe thứ 3 chở là

16+12=28 tấn

169+296x2

=169+592

=761

169+296x2

=169+592

=761

\(A\left(1\right)=a\cdot1^2+b\cdot1+c=a+b+c\)

\(A\left(-3\right)=a\cdot\left(-3\right)^2+b\cdot\left(-3\right)+c=9a-3b+c\)

Ta có:

\(A\left(1\right)+A\left(-3\right)=\left(a+b+c\right)+\left(9a-3b+c\right)\\ =10a-2b+2b\\ =2\left(5a+c\right)-2b\\ =2b-2b=0\\ =>A\left(1\right)+A\left(-3\right)=0=>A\left(1\right)=-A\left(-3\right)\)

Ta có:\(A\left(1\right)\cdot A\left(-3\right)=A\left(-1\right)\cdot\left[-A\left(-1\right)\right]=-\left[A\left(-1\right)\right]^2\le0\)

$A\left(1\right)=a\cdot 1^2+b\cdot 1+c=a+b+c$

$A\left(-3\right)=a\cdot {\left(-3\right)}^2+b\cdot \left(-3\right)+c=9a-3b+c$

Ta có:

$A\left(1\right)+A\left(-3\right)=\left(a+b+c\right)+\left(9a-3b+c\right)=10a-2b+2b=2\left(5a+c\right)-2b=2b-2b=0=>A\left(1\right)+A\left(-3\right)=0=>A\left(1\right)=-A\left(-3\right)$

Ta có:$A\left(1\right)\cdot A\left(-3\right)=A\left(-1\right)\cdot \left[-A\left(-1\right)\right]=-{\left[A\left(-1\right)\right]}^2\le 0$

A.Complete the sentences with correct perfect modals:

1. You didn't need to buy that book about the oceans. I could have lent you my copy.

2. I don't know why Simon isn't here yet, but I suppose he must have missed the bus.

3. The city centre is no longer covered in graffiti; the city council must have cleaned it up.

4. You should have told me you were going to be late instead of making me wait so long!

5. Mark should have brought sunblock because it rained all weekend.

6. They must have eaten all that food; there was so much of it!

7. The hikers should have returned by now; I wonder where they are.

B. Rewrite the sentences using the words in brackets:

1. Lunch was provided so they didn't need to take sandwiches.

2. She studied hard so she should have passed the exam.

3. I think he's foreign so he might not have understood you.

4. John can't be in Rome - I saw him earlier.

5. You ought to have listened to my advice.

6. Why mightn't you introduce me to your friends?

C. Complete the second sentences so that they have a similar meaning to the first sentences using the words in bold:

1. Caged animals are miserable, wouldn't you agree?

2. You must pay a membership fee before you can join the animal society.

3. We are bound to get some rain today; I can feel it in my bones.

4. My Internet connection will not work; I've been trying to get online all day.

5. The documentary on whales ought to be interesting for my class.

A. Complete the sentences with correct perfect modals.

1. You didn't need to buy that book about the oceans. I ..would have lent...(lend) you my copy.

2. I don't know why Simon isn't here yet, but I suppose he…might have missed.. (miss) the bus.

3. The city centre is no longer covered in graffiti; the city council ...must have cleaned.... (clean) it up.

4. You ....should have told... (tell) me you were going to be late instead of making me wait so long!

5. Mark …should have brought.(bring) sunblock because it rained all weekend.

6. They ...couldn't have eaten... (eat) all that food; there was so much of it!

7. The hikers ..should have returned...(return) by now; I wonder where they are.

giúp mik với. Mik cần gấp

câu 1D  câu 2 C  câu 3

1. $4\frac{1}{24}-\frac{35}{8}:\left(\frac74-\frac{7}{12}\right)+\frac{1}{16}\times\frac23$

$=\frac{97}{24}-\frac{35}{8}:\frac{7}{6}+\frac{1}{24}$

$=\left(\frac{97}{24}+\frac{1}{24}\right)-\frac{35}{8}\times\frac67$

$=\frac{49}{12}-\frac{15}{4}$

$=\frac{49}{12}-\frac{45}{12}=\frac{4}{12}=\frac13$

2.

a. $\frac{7}{12}+\frac27+\frac{5}{12}+\frac57-\frac{3}{11}$

$=\left(\frac{7}{12}+\frac{5}{12}\right)+\left(\frac27+\frac57\right)-\frac{3}{11}$

$=1+1-\frac{3}{11}$

$=2-\frac{3}{11}=\frac{22}{11}-\frac{3}{11}=\frac{19}{11}$

b. $3,54\times73+0,23\times46+3,54\times27+0,77\times46$

$=3,54\times(73+27)+46\times(0,23+0,77)$

$=3,54\times100+46\times1$

$=354+46=400$

$Toru$

A.Complete the sentences with correct perfect modals:

1. You didn't need to buy that book about the oceans. I could have lent you my copy.

2. I don't know why Simon isn't here yet, but I suppose he must have missed the bus.

3. The city centre is no longer covered in graffiti; the city council must have cleaned it up.

4. You should have told me you were going to be late instead of making me wait so long!

5. Mark should have brought sunblock because it rained all weekend.

6. They must have eaten all that food; there was so much of it!

7. The hikers should have returned by now; I wonder where they are.

B. Rewrite the sentences using the words in brackets:

1. Lunch was provided so they didn't need to take sandwiches.

2. She studied hard so she should have passed the exam.

3. I think he's foreign so he might not have understood you.

4. John can't be in Rome - I saw him earlier.

5. You ought to have listened to my advice.

6. Why mightn't you introduce me to your friends?

C. Complete the second sentences so that they have a similar meaning to the first sentences using the words in bold:

1. Caged animals are miserable, wouldn't you agree?

2. You must pay a membership fee before you can join the animal society.

3. We are bound to get some rain today; I can feel it in my bones.

4. My Internet connection will not work; I've been trying to get online all day.

5. The documentary on whales ought to be interesting for my class.

A. Complete the sentences with correct perfect modals.

1. You didn't need to buy that book about the oceans. I ..would have lent...(lend) you my copy.

2. I don't know why Simon isn't here yet, but I suppose he…might have missed.. (miss) the bus.

3. The city centre is no longer covered in graffiti; the city council ...must have cleaned.... (clean) it up.

4. You ....should have told... (tell) me you were going to be late instead of making me wait so long!

5. Mark …should have brought.(bring) sunblock because it rained all weekend.

6. They ...couldn't have eaten... (eat) all that food; there was so much of it!

7. The hikers ..should have returned...(return) by now; I wonder where they are.

Bạn vô đây nhé!

Bn vào trang cá nhân của bn mà mik muốn kb, xong bạn ấn vào chữ kb ở đó, cuối cùng là chờ người đó đồng ý thui. Tk ạ!!

7/12 + 2/7 + 5/12 + 2/7 - 3/11

= (7/12 + 5/12) + (2/7 + 5/7) - 3/11

= 1 + 1 - 3/11

= 2 - 3/11

= 19/11

sos

A.Complete the sentences with correct perfect modals:

1. You didn't need to buy that book about the oceans. I could have lent you my copy.

2. I don't know why Simon isn't here yet, but I suppose he must have missed the bus.

3. The city centre is no longer covered in graffiti; the city council must have cleaned it up.

4. You should have told me you were going to be late instead of making me wait so long!

5. Mark should have brought sunblock because it rained all weekend.

6. They must have eaten all that food; there was so much of it!

7. The hikers should have returned by now; I wonder where they are.

B. Rewrite the sentences using the words in brackets:

1. Lunch was provided so they didn't need to take sandwiches.

2. She studied hard so she should have passed the exam.

3. I think he's foreign so he might not have understood you.

4. John can't be in Rome - I saw him earlier.

5. You ought to have listened to my advice.

6. Why mightn't you introduce me to your friends?

A. Complete the sentences with correct perfect modals.

1. You didn't need to buy that book about the oceans. I ..would have lent...(lend) you my copy.

2. I don't know why Simon isn't here yet, but I suppose he…might have missed.. (miss) the bus.

3. The city centre is no longer covered in graffiti; the city council ...must have cleaned.... (clean) it up.

4. You ....should have told... (tell) me you were going to be late instead of making me wait so long!

5. Mark …should have brought.(bring) sunblock because it rained all weekend.

6. They ...couldn't have eaten... (eat) all that food; there was so much of it!

7. The hikers ..should have returned...(return) by now; I wonder where they are.