Giúp vs cảm ơn mn trc!
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DM
4
QN
2
DT
Đỗ Thanh Hải
CTVVIP
21 tháng 6 2021
2 Without his sister's help, John couldn't have done his homework
3 Instead of driving to work, I go by bus today
4 Mai doesn't mind giving you a hand
5 They don't know much about English
6 The noise prevented him from sleeping
7 The police have investigated the case for a week
8 We never had an intention of travelling abroad
9 Mary is believed to get the scholatship
10 Instrad of slowing down, he drove faster
HV
10 tháng 11 2021
1 had gone to bed, we watched television
2 had a swim for 5 days
3 met him for 5 months
4 gone to this club since 1999
5 come to this city since July
6 learned French since 2001
7 played chess for 3 years
8 smoked for 5 years
9 there, Jack had left the office
10 I have visited England
11 the first time I have met this lady
12 I was having dinner, the phone rang
13 we arrived there, David had left the party
14 used to wear glasses before
15 ages since we last went to a concert
16 saw her friends when she left for the United states
17 the first time I have stayed in such an expensive hotel
TK
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T
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NA
2
N
6 tháng 11 2021
Bài 1:
\(54\left(\dfrac{km}{h}\right)=15\left(\dfrac{m}{s}\right);9\left(\dfrac{m}{s}\right)=32,4\left(\dfrac{km}{h}\right)\)
Baì 2:
\(t'=s':v'=5:\left(5.3,6\right)=\dfrac{5}{18}h\)
\(\Rightarrow v_{tb}=\dfrac{s'+s''}{t'+t''}=\dfrac{5+3,8}{\dfrac{5}{18}+\left(\dfrac{15}{60}\right)}\simeq16,67\left(\dfrac{km}{h}\right)\)
7 tháng 11 2021
Câu 2:
\(\Leftrightarrow\left(x+2\right)\left(10x+3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-2\\x=-\dfrac{3}{10}\end{matrix}\right.\)
2 tháng 10 2021
\(A1+2=A2\)
\(\overline{A}\) =\(\dfrac{A1\cdot54+\cdot\left(A1+2\right)\cdot46}{100}\)=79.92
\(\Leftrightarrow\)A1=79\(\Rightarrow\)A2=81
a) \(\frac{-4}{9}\times\frac{7}{15}+\frac{4}{-9}\times\frac{8}{15}\)
=\(\frac{-4}{9}\times\left(\frac{7}{15}+\frac{8}{15}\right)\)
=\(\frac{-4}{9}\times1\)
=\(\frac{-4}{9}\)
b ) \(\frac{5}{-4}\times\frac{16}{25}+\frac{-5}{4}\times\frac{9}{25}\)
=\(\frac{-5}{4}\times\left(\frac{16}{25}+\frac{9}{25}\right)\)
=\(\frac{-5}{4}\times1\)
=\(\frac{-5}{4}\)
-4/9 . 7/15 + 4/-9 . 8/15
= ( -4/9 + 4/-9 ) + ( 7/15 + 8/15 )
= \(-\frac{8}{9}\)+ 1
= 1/9