giúp vs
cần gấp
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Phản hồi đến em!
1. The last time she went out with him was 5 years ago.
2. This is the first time we have seen such a cruel mother.
3. We haven't seen Mr.Johns for 2 years.
4. I haven't visited the USA before.
5. I began learning English 10 years ago.
6. The last time the Pikes visited Paris was 2 years ago.
7. I haven't written to him for a week.
8. It's been (=has been) 6 years since Mary started learning French.
9. My uncle started working in that factory 10 years ago.
10. My old friend has worked on that farm since 2005.
11. It's been a long time since my mother started having this machine.
12. My father hasn't drank champagne for 10 years.
12. We last saw Mary when we were in the university.
14. I haven't gone swimming since I was in Spain.
15. She has moved to London for 20 years.
16. I haven't seen John sice he was leaving for Edinburgh.
17. The last time I saw her was 3 years ago. / It's 3 years since I last saw her.
Áp dụng tính chất của dãy tỉ số bằng nhau, ta được:
\(\dfrac{a}{\dfrac{1}{3}}=\dfrac{b}{\dfrac{1}{4}}=\dfrac{c}{\dfrac{1}{5}}=\dfrac{a+b+c}{\dfrac{1}{3}+\dfrac{1}{4}+\dfrac{1}{5}}=\dfrac{94}{\dfrac{47}{60}}=120\)
Do đó: a=40; b=30; c=24
\(A=\dfrac{31\cdot\left(31^{12}-1\right)}{31\left(31^{13}+1\right)}=\dfrac{31^{13}+1-32}{31\left(31^{13}+1\right)}=\dfrac{1}{31}-\dfrac{32}{31^{14}+31}\)
\(B=\dfrac{31\left(31^{13}-1\right)}{31\left(31^{14}+1\right)}=\dfrac{1}{31}-\dfrac{32}{31^{15}+31}\)
Dễ thấy \(31^{14}+31< 31^{15}+31\Rightarrow\dfrac{32}{31^{14}+31}>\dfrac{32}{31^{15}+31}\\ \Rightarrow\dfrac{1}{31}-\dfrac{32}{31^{14}+31}< \dfrac{1}{31}-\dfrac{32}{31^{15}+31}\)
Vậy A < B
1 do you do
2 had done - went
3 went - had read
4 will attend
5 hadn't worn
6 to be
7 weren't sleeping - were playing
8 to be
9 had lived - moved
10 locking
11 had work - retired
12 told - had learned
13 won't call
14 had met
do you do
had done-went
went- had read
will attend
hadn't worn
to be
a: Xét tứ giác AEHF có
\(\widehat{AEH}=\widehat{AFH}=\widehat{FAE}=90^0\)
Do đó: AEHF là hình chữ nhật
đây là toán l1??????????????????