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Những câu hỏi liên quan
NT
0
TL
1
K
27 tháng 5 2021
Part 1:
1. with
2. does
3. after
4. if
5. where
6. I won't
Part 2:
1B 2F 3A 4E 5C 6D
Part 3:
1. invited
2. will play
3. have just won
4. be cleaned
5. to take
6. beautifully
7. impression
Part 4:
1. read -> reading
2. disappointing -> disappointed
3. environment -> environmental
4. who -> that
Part 5:
1. the bad weather
2. are made to study
3. were good at learning
4. going to the English
TL
2
MN
27 tháng 5 2021
Part 1 :
1. so
2. forward
3. which
4.didn't
5. if
6. although
Part 2 :
1.C
2.E
3.A
4.F
5.B
6.D
18 tháng 5 2021
part 1
1 about
2 have
3 after
4 because
5 which
6 if
part 2
1a 2c 3g 4d 5b 6f
part 3
1 have mentioned
2 will reduce
3 to turn
4 spending
5 to be taken
6 modernize
7 unpolluted
8 destruction
part 4
1 although -> because
2 can -> could
part 5
1 which was read
2 he tried hard
3 they had enough money
4 will be held in
part 6
1 that
2 frequently
3 cause
4 constant
part 7
1T 2F 3F 4F
19 tháng 5 2021
1.θ
2.Although
3.doen't
4.on
5.Although
6.or
Part 2:
1-A
2-F
3-B
4-C
5-D
6-E
Part 3:
1.beautifully
2.was watching
3.didn't finish
4.was built
5.is lying
6.surprisingly
7.left
8.independence
19 tháng 5 2021
Part 5:
1.The policeman suggested checking everything once more
2.The castle is said that to be built in the 19th century
3.We climbed on top of the tower and we had a beautiful view from there
4.She told me she would go to China next week with her parents
8 tháng 12 2023
Để hệ phương trình có nghiệm duy nhất thì \(\dfrac{m}{3}< >-\dfrac{1}{m}\)
=>\(m^2\ne-3\)(luôn đúng)
Ta có: \(\left\{{}\begin{matrix}mx-y=2\\3x+my=3m\end{matrix}\right.\)
=>\(\left\{{}\begin{matrix}y=mx-2\\3x+m\left(mx-2\right)=3m\end{matrix}\right.\)
=>\(\left\{{}\begin{matrix}y=mx-2\\3x+m^2x-2m=3m\end{matrix}\right.\)
=>\(\left\{{}\begin{matrix}y=mx-2\\x\left(m^2+3\right)=5m\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=\dfrac{5m}{m^2+3}\\y=m\cdot\dfrac{5m}{m^2+3}-2\end{matrix}\right.\)
=>\(\left\{{}\begin{matrix}x=\dfrac{5m}{m^2+3}\\y=\dfrac{5m^2-2m^2-6}{m^2+3}=\dfrac{3m^2-6}{m^2+3}\end{matrix}\right.\)
\(\left(x+y\right)\cdot\left(m^2+3\right)+8=0\)
=>\(\dfrac{5m+3m^2-6}{m^2+3}\cdot\left(m^2+3\right)+8=0\)
=>\(3m^2+5m-6+8=0\)
=>\(3m^2+5m+2=0\)
=>(m+1)(3m+2)=0
=>\(\left[{}\begin{matrix}m=-1\\m=-\dfrac{2}{3}\end{matrix}\right.\)
PK
5
TA
18 tháng 5 2021
`sin3x sinx+sin(x-π/3) cos (x-π/6)=0`
`<=> 1/2 (cos2x - cos4x) + 1/2(-sin π/6 + sin (2x-π/2)=0`
`<=> cos2x-cos4x-1/2+ sin(2x-π/2)=0`
`<=>cos2x-cos4x-1/2+ sin2x .cos π/2 - cos2x. sinπ/2=0`
`<=> cos2x - cos4x - cos2x = 1/2`
`<=> cos4x = cos(2π)/3`
`<=>` \(\left[{}\begin{matrix}4x=\dfrac{2\text{π}}{3}+k2\text{π}\\4x=\dfrac{-2\text{π}}{3}+k2\text{π}\end{matrix}\right.\)
`<=>` \(\left[{}\begin{matrix}x=\dfrac{\text{π}}{6}+k\dfrac{\text{π}}{2}\\x=-\dfrac{\text{π}}{6}+k\dfrac{\text{π}}{2}\end{matrix}\right.\)
19 tháng 5 2021
Part 1
1 if
2 after
3 that
4 so
5 should
6 from
Part 2
1b 2e 3a 4f 5c 6d
Part 3
1 conservationists
2 to take
3 hasn't provided
4 works
5 disappointed
6 achievement
7 polluted
8 dissolve
Part 4
1 will get -> get
2 amazing -> amazed
Part 5
1 use fresh water economically
2 school because the bus
3 they should keep
4 which is in this
Part 6
1 fond
2 watching
3 listened
4 or
Part 7
1T 2F 3T 4F