giúp mìn với đang gấp lắm
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CN
1
W
6 tháng 4 2022
1 She said that she was coming
2 She said that she wouldn't see me the following day
3 She said that he worked in a bank
4 She said that he was living in Paris for a few months
5 Lan said that she would be very busy the next day
6 Thu said that all the students would have a meeting the following sunday
7 Tam said that she could swim acroos that river
8 His sister said that she didn't buy that book
9 The boy said that they had to try their best to win the match
10 Her father said to her that she could go to the movies with her friends
11 Her classmate said that Lan was the most intellligent girl in their class
12 The teacher said that the sun rised in the east
HL
3
mìn đang cần gấp mụi ngừi giúp mìn vs ah :(
TD
14
NV
Nguyễn Việt Lâm
Giáo viên
13 tháng 6 2021
Tất cả k dưới đây đều là \(k\in Z\)
6.
\(\Leftrightarrow\sqrt{3}cot\left(3x-\dfrac{\pi}{3}\right)=1\)
\(\Leftrightarrow cot\left(3x-\dfrac{\pi}{3}\right)=\dfrac{1}{\sqrt{3}}\)
\(\Leftrightarrow cot\left(3x-\dfrac{\pi}{3}\right)=cot\left(\dfrac{\pi}{3}\right)\)
\(\Leftrightarrow3x-\dfrac{\pi}{3}=\dfrac{\pi}{3}+k\pi\)
\(\Leftrightarrow3x=\dfrac{2\pi}{3}+k\pi\)
\(\Leftrightarrow x=\dfrac{2\pi}{9}+\dfrac{k\pi}{3}\)
NV
Nguyễn Việt Lâm
Giáo viên
13 tháng 6 2021
7.
\(\Leftrightarrow\sqrt{3}tan\left(3x-15^0\right)=-1\)
\(\Leftrightarrow tan\left(3x-15^0\right)=-\dfrac{1}{\sqrt{3}}\)
\(\Leftrightarrow tan\left(3x-15^0\right)=tan\left(-30^0\right)\)
\(\Leftrightarrow3x-15^0=-30^0+k180^0\)
\(\Leftrightarrow3x=-15^0+k180^0\)
\(\Leftrightarrow x=-3^0+k60^0\)
NN
1
17 tháng 7 2017
\(\left(2x+1\right)\left(2x+3\right)\left(x+1\right)^2-18=0\)
\(\Leftrightarrow\left(x^2+2x+1\right)\left(4x^2+8x+3\right)-18=0\)
Đặt \(x^2+2x+1=a\ge0\)
\(\Rightarrow a\left(4a-1\right)-18=0\)
\(\Leftrightarrow4a^2-a-18=0\)
\(\Leftrightarrow\left(4a^2+8a\right)+\left(-9a-18\right)=0\)
\(\Leftrightarrow\left(a+2\right)\left(4a-9\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}a=-2\left(l\right)\\a=\frac{9}{4}\end{cases}}\)
\(\Rightarrow x^2+2x+1=\frac{9}{4}\)
\(\Leftrightarrow4x^2+8x-5=0\)
\(\Leftrightarrow\left(4x^2-2x\right)+\left(10x-5\right)=0\)
\(\Leftrightarrow\left(2x-1\right)\left(2x+5\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x=\frac{1}{2}\\x=-\frac{5}{2}\end{cases}}\)
SN
23 tháng 3 2022
Mọi ngừi làm giúp mìn với!!! gấp lắm!!!
As you all know, tomorrow (15)..will be.... the first day of the annual Environment Awareness Month at South Middle School. Over the course of next month, there will be (16) .....many....events to raise awareness about different environmental issues and how to ‘go green’. The teaching staffs at South Middle School ask students to learn this opportunity seriously. Environmental issues are (17) ......very........ important and affecting every one of us. At the end of the month, we hope you can learn something new and apply them to your daily lives. If you have any questions for (18) .....it..., please contact Ms Simon at her office.
a, góc B1 = góc A1 = \(105^o\)( slt)
mà góc A1 = \(\frac{7}{5}\)A2
=> \(105^o\)=\(\frac{7}{5}\).A2
=>A2 = \(105^o:\frac{7}{5}=75^o\)