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28 tháng 2 2021

`x+y=3`

`<=>(x+y)^3=9`

`<=>x^2+2xy+y^2=9`

`<=>2xy+5=9`

`<=>2xy=4`

`<=>xy=2`

`<=>x^2-xy+y^2=3`

`=>M=(x+y)(x^2-xy+y^2)`

`=3.3`

`=9`

28 tháng 2 2021

x+y=3

⇔(x+y)2=9

⇔x2+2xy+y2=9

⇔2xy+5=9(Vì x2+y2=5)

⇔2xy=4

⇔xy=2

Có : x2+y2=5

\(\Rightarrow\)x2+y2-xy =3

Có M=x3+y3

\(\Rightarrow\)M=(x+y)(x2−xy+y2)

\(\Rightarrow\)M=3.3

\(\Rightarrow\)M=9

26 tháng 12 2021

\(\dfrac{1}{\sqrt{5}}-\sqrt{3}-\dfrac{1}{\sqrt{5}}+\sqrt{3}\)

\(\dfrac{1}{\sqrt{5}}-\dfrac{1}{\sqrt{5}}-\sqrt{3}+\sqrt{3}\)

=0

10 tháng 8 2017

V/ tìm và sửa lỗi sai

1. I (1)can't (2)understand (3)what that tourist (4)is said

-> 4 said

2. We are (1)going to (2)give David (3)a big (4)surprising

-> 4 surprise

3. Those (1)at work must pay (2)to the welfare (3)benefits (4)in this country

-> 3 for the welfare

4. John (1)will have received the (2)papers (3)from -> by (4)tomorrow

5. He (1)works (2)hardly -> hard in (3)order (4)to pass the examination

6. The man (1)said he (2)was taking the train (3)tomorrow -> the following day (4)evening

7. That girl (1)allowed me (2)use -> to use her computer (3)at any time i (4)want

8. You (1)should (2)do morning (3)exercises (4)regular -> regularly

10 tháng 8 2017

V/ tìm và sửa lỗi sai

1. I (1)can't (2)understand (3)what that tourist (4)is said

-> said

2. We are (1)going to (2)give David (3)a big (4)surprising

->surprise

3. Those (1)at work must pay (2)to the welfare (3)benefits (4)in this country

-> for the welfare

4. John (1)will have received the (2)papers (3)from (4)tomorrow

-> by

5. He (1)works (2)hardly in (3)order (4)to pass the examination

-> hard

6. The man (1)said he (2)was taking the train (3)tomorrow (4)evening

-> the following

7. That girl (1)allowed me (2)use her computer (3)at any time i (4)want

-> to use

8. You (1)should (2)do morning (3)exercises (4)regular

-> regularly

13 tháng 11 2021

design

13 tháng 11 2021

Design

11 tháng 8 2017

1. Vicky (1)said she (2)didn't know (3)where Michael (4)is => was

2. The womam (1)is => bỏ ''is'' standing next (2)to our teacher (3)is (4)my mother

3. He (1)is (2)proud (3)of his (4)wise=> wisdom

4. I (1)was so (2)excitement => excited (3)about the football match (4)last night

5. She (1)lives =>lived (2)in Rome (3)when she (4)was a little girl

6. He (1)will be (2)back (3)from => between 5:25 (4)and 6:20

11 tháng 8 2017

1. Vicky (1)said she (2)didn't know (3)where Michael (4)was

2. The womam (1) bỏ "is" standing next (2)to our teacher (3)is (4)my mother

3. He (1)is (2)proud (3)of his (4)wisdom

4. I (1)was so (2)excited (3)about the football match (4)last night

5. She (1) lived (2)in Rome (3)when she (4)was a little girl

6. He (1)will be (2)back (3) between 5:25 (4)and 6:20